Interstitial deletion of 1p22.2p31.1 and medium-chain acyl-CoA dehydrogenase deficiency in a patient with global developmental delay

We report on a 6-year-old girl who presented at 6 months of age with seizures, delayed psychomotor development and mild facial dysmorphism. A small muscular ventricular septal defect was documented on echocardiogram and brain MRI showed a frontal brain anomaly. Urine organic acid analysis revealed dicarboxylic aciduria, and plasma acylcarnitine analysis showed marked elevation of octanoyl (C8) and decanoyl (C10) carnitines with C8:C10 ratio of 9:1. These results were indicative of medium chain acyl-CoA dehydrogenase deficiency. ACADM gene sequencing showed an apparent homozygous c.166G > C (Ala31Pro) missense mutation in exon 3; however, only the mother was found to be a carrier of this novel missense mutation. This finding along with non-regressive developmental delay prompted further karyotype and genomic investigations. An interstitial deletion of chromosome 1 was detected by repeat G-banding: 46,XX,del(1)(p22.2p31.1). Parental karyotypes were normal. The deletion was characterized by array CGH analysis using a 1 Mb BAC/PAC array platform. Clones deleted extended from RP11-88B10 (1p31.1) to RP5-1007M22 (1p22.2), a 15.5 Mb deletion which includes the ACADM locus. Clinical review of 6/7 cases of interstitial deletions with breakpoints of 1p22 and 1p31/32, including the patient in this report, indicate a variable phenotype. Thus, although G-band breakpoints are similar, common breakpoints for these alterations are unlikely. This is the first report of a patient with fatty acid oxidation defect caused by a mutation in combination with an interstitial chromosomal deletion.     

Bcl-xL is associated with the anti-apoptotic effect of IL-15 on the survival of CD56(dim) natural killer cells

Human NK cells can be distinguished into CD56(bright) and CD56(dim) subsets based on cell surface CD56 density. It has been shown that IL-2 and IL-15 have opposing effects on life and death of CD8(+) T cells. However, the roles of IL-2 and IL-15 in regulating these two NK cell subsets remain elusive. In this study, we comparatively analyzed the effects of IL-2 and IL-15 on two NK cell subsets. IL-15 improved the proliferation and activation of CD56(dim) NK cells in long-term cord blood mononuclear cell culture, but IL-2 only maintained the survival of CD56(bright) NK cells. The percentage of CD56(+)Annexin V(+) NK cells cultured with IL-15 was lower than that with IL-2; moreover, most of Annexin V(+) NK cells were primarily in the CD56(dim) NK cells. IL-15 cultured NK cells expressed higher level of Bcl-xL than IL-2 cultured cells. Furthermore, IL-15 more strongly upregulated CD25 expression and better maintained the expression of IL-15Ralpha than IL-2. These results suggest that CD56(dim) NK cells undergo apoptosis when cultured with IL-2, but IL-15 inhibits their apoptosis and Bcl-xL is associated with the anti-apoptotic effect of IL-15. So IL-15 played a crucial role in sustaining long-lasting functions of CD56(dim) NK cells.     

Differential regulation of prohormone convertase 1/3, prohormone convertase 2 and phosphorylated cyclic-AMP-response element binding protein by short-term and long-term morphine treatment: implications for understanding the "switch" to opiate addiction

Drug addiction is a state of altered brain reward and self-regulation mediated by both neurotransmitter and hormonal systems. Although an organism's internal system attempts to maintain homeostasis when challenged by exogenous opiates and other drugs of abuse, it eventually fails, resulting in the transition from drug use to drug abuse. We propose that the attempted maintenance of hormonal homeostasis is achieved, in part, through alterations in levels of processing enzymes that control the ratio of active hormone to pro-hormone. Two pro-hormone convertases, PC1/3 and PC2 are believed to be responsible for the activation of many neurohormones and expression of these enzymes is dependent on the presence of a cyclic-AMP response element (CRE) in their promoters. Therefore, we studied the effects of short-term (24-h) and long-term (7-day) morphine treatment on the expression of hypothalamic PC1/3 and PC2 and levels of phosphorylated cyclic-AMP-response element binding protein (P-CREB). While short-term morphine exposure down-regulated, long-term morphine exposure up-regulated P-CREB, PC1/3 and PC2 protein levels in the rat hypothalamus as determined by Western blot analysis. Quantitative immunofluorescence studies confirmed these regulatory actions of morphine in the paraventricular and dorsomedial nucleus of the hypothalamus. Specific radioimmunoassays demonstrated that the increase in PC1/3 and PC2 levels following long-term morphine led to increased TRH biosynthesis as evidence by increased TRH/5.4 kDa C-terminal proTRH-derived peptide ratios in the median eminence. Promoter activity experiments in rat somatomammotrope GH3 cells containing the mu-opioid receptor demonstrated that the CRE(s) in the promoter of PC1/3 and PC2 is required for morphine-induced regulation of PC1/3 and PC2. Our data suggest that the regulation of the prohormone processing system by morphine may lead to alterations in the levels of multiple bioactive hormones and may be a compensatory mechanism whereby the organism tries to restore its homeostatic hormonal milieu. The down-regulation of PC1/3, PC2 and P-CREB by short-term morphine and up-regulation by long-term morphine treatment may be a signal mediating the switch from drug use to drug abuse.     

Possibilities and potential roles of estrogen in the pathogenesis of proliferation hemangiomas formation

Hemangiomas, often categorized as angiogenic diseases, are the most common tumors of infancy, the life span of which is generally divided into proliferating phase, involuting phase, and involuted phase. Despite their high prevalence, the mechanism leading to proliferation hemangiomas formation is poorly understood and the best approach to their management remains controversial. None of the current therapeutic modalities is ideal, partly because the pathogenesis of hemangioma and the mechanism of its proliferation are far from clear. Many clues reveal that estrogen has an important role in developing the vascular system, experimental and clinical evidences accumulated in recent years also suggest the potential for estrogen to influence neovascularization. Based on those, we hypothesize that estrogen play a potential role in the development of hemangiomas, mainly by regulating some key angiogenic factors, including MMP-9, EPCs, VEGF, NO, etc. Accepting the hypothesis to be correct, a therapy that identify estrogen as a potential target for the design of new, more specific treatments can be used to prevent the proliferation hemangiomas formation. The hypothesis may lead a new direction in the study of mechanisms for proliferation hemangiomas formation, and further study of the precise mechanisms for estrogen-induced hemangiomas will produce effective antiestrogens and estrogen receptor antagonists as new medication for the very difficult problem.     

CXCR3 determines strain susceptibility to murine cerebral malaria by mediating T lymphocyte migration toward IFN-gamma-induced chemokines

Cerebral malaria (CM) results from the binding of infected erythrocytes and leukocytes to brain endothelia. The precise mechanisms underlying lymphocyte recruitment and activation in CM remain unclear. Therefore, the expression of various chemokines was quantified in brains of mice infected with Plasmodium berghei ANKA (PbA). Several chemokines attracting monocytes and activated T-lymphocytes were expressed at high levels. Their expression was almost completely abrogated in IFN-gamma ligand and receptor KO mice, indicating that IFN-gamma is an essential chemokine inducer in vivo. Surprisingly, the expression levels of chemokines, IFN-gamma and also adhesion molecules in the brain were not lower in CM-resistant Balb/c and DBA/2 mice compared to CM-sensitive C57BL/6 and DBA/1 mice, although T lymphocyte sequestration in the brain was significantly less in CM-resistant than in CM-sensitive mice. This difference correlated with a higher up-regulation of the CXC chemokine receptor (CXCR)-3 on splenic T cells and a higher chemotactic response to IFN-gamma-inducible protein-10 (IP-10) in C57BL/6 compared to Balb/c mice. In conclusion, parasite-induced IFN-gamma in the brain results in high local expression levels of specific chemokines for monocytes and lymphocytes. The strain-dependent susceptibility to develop CM is more related to the expression of CXCR3 in circulating leukocytes than to the chemokine expression levels in the brain.     

Parathyroid hormone signaling through low-density lipoprotein-related protein 6

Intermittent administration of PTH stimulates bone formation, but the precise mechanisms responsible for PTH responses in osteoblasts are only incompletely understood. Here we show that binding of PTH to its receptor PTH1R induced association of LRP6, a coreceptor of Wnt, with PTH1R. The formation of the ternary complex containing PTH, PTH1R, and LRP6 promoted rapid phosphorylation of LRP6, which resulted in the recruitment of axin to LRP6, and stabilization of β-catenin. Activation of PKA is essential for PTH-induced β-catenin stabilization, but not for Wnt signaling. In vivo studies confirmed that PTH treatment led to phosphorylation of LRP6 and an increase in amount of β-catenin in osteoblasts with a concurrent increase in bone formation in rat. Thus, LRP6 coreceptor is a key element of the PTH signaling that regulates osteoblast activity.     

Molecular identity and functional properties of a novel T-type Ca2+ channel cloned from the sensory epithelia of the mouse inner ear

The molecular identity of non-Ca_v1.3 channels in auditory and vestibular hair cells has remained obscure, yet the evidence in support of their roles to promote diverse Ca²⁺-dependent functions is indisputable. Recently, a transient Ca_v3.1 current that serves as a functional signature for the development and regeneration of hair cells has been identified in the chicken basilar papilla. The Ca_v3.1 current promotes spontaneous activity of the developing hair cell, which may be essential for synapse formation. Here, we have isolated and sequenced the full-length complementary DNA of a distinct isoform of Ca_v3.1 in the mouse inner ear. The channel is derived from alternative splicing of exon14, exon25A, exon34, and exon35. Functional expression of the channel in Xenopus oocytes yielded Ca²⁺ currents, which have a permeation phenotype consistent with T-type channels. However, unlike most multiion channels, the T-type channel does not exhibit the anomalous mole fraction effect, possibly reflecting comparable permeation properties of divalent cations. The Ca_v3.1 channel was expressed in sensory and nonsensory epithelia of the inner ear. Moreover, there are profound changes in the expression levels during development. The differential expression of the channel during development and the pharmacology of the inner ear Ca_v3.1 channel may have contributed to the difficulties associated with identification of the non-Ca_v1.3 currents.     

Characterization of extensively drug-resistant Mycobacterium tuberculosis clinical isolates in China

Thirteen extensively drug-resistant tuberculosis isolates which were highly resistant to a broad spectrum of antituberculosis drugs were identified from 1,926 clinical isolates in China. They had highly diverse mycobacterial interspersed repetitive-unit-variable-number tandem-repeat patterns. Most, but not all, of the drug target genes had mutations contributing to resistance to the corresponding drug.     

Antigen-presenting effects of effector memory Vγ9Vδ2 T cells in rheumatoid arthritis

Rheumatoid arthritis is an autoimmune disease that primarily affects the limbs, but the pathogenic mechanism remains unclear. γδ T cells, a T-cell subpopulation, are characterized by multiple biological functions and associated with a variety of diseases. This study investigated the antigen-presenting effects of γδ T cells and their relationship with rheumatoid arthritis development. We found that Vγ9Vδ2 T cells (the predominant subtype of γδ T cells in peripheral blood) were activated by isopentenyl pyrophosphate to continuously proliferate and differentiate into effector memory cells. The effector memory Vγ9Vδ2 T cells exhibited phenotypic characteristics of specific antigen-presenting cells, including high HLA-DR and CD80/86 expression. These Vγ9Vδ2 T cells could present soluble antigens and synthetic peptides to CD4(+) T cells. Vγ9Vδ2 T cells with different phenotypes showed different cytokine secretion patterns. Effector memory Vγ9Vδ2 T cells simultaneously secreted not only interferon (IFN)-γ but also IL-17. The peripheral blood and joint synovial fluid from RA patients contained numerous heterogeneous γδ T cells that were predominantly effector memory Vγ9Vδ2 T cells with the ability to secrete inflammatory factors. We also found that γδ T cells had a similar antigen-presenting capability to B cells. These results suggest that during the development of rheumatoid arthritis, γδ T cells can aggravate immune dysfunction and produce abnormal immune damage by secreting cytokines and inducing inflammatory cells to participate in synergistic inflammatory responses. Furthermore, γδ T cells can behave similarly to B cells to present viral peptides and autoantigen peptides to CD4(+) T cells, thus sustaining CD4(+) T-cell activation.     

Effective inhibition of the early copper ion burst release with ultra-fine grained copper and single crystal copper for intrauterine device application

To solve the main problems of existing coarse grained copper (CG Cu) intrauterine devices (IUD)-namely burst release and a low transfer efficiency of the cupric ions during usage-ultra-fine grained copper (UFG Cu) and single crystal copper (SC Cu) have been investigated as potential substitutes. Their corrosion properties with CG Cu as a control have been studied in simulated uterine fluid (SUF) under different conditions using electrochemical measurement methods. Long-term immersion of UFG Cu, SC Cu and CG Cu samples in SUF at 37 °C have been studied for 300 days. A lower copper ion burst release and a higher efficiency release of cupric ions were observed for UFG Cu and SC Cu compared with CG Cu in the first month of immersion and 2 months later. The respective corrosion mechanisms for UFG Cu, SC Cu and CG Cu in SUF are proposed. In vitro biocompatibility tests show a better cellular response to UFG Cu and SC Cu than CG Cu. In terms of instantaneous corrosion behavior, long-term corrosion performance and in vitro biocompatibility, the three pure copper materials follow the order: UFG Cu>SC Cu>CG Cu, which indicates that UFG Cu could be the most suitable candidate material for intrauterine devices.