A review is presented of selected recent topics in electrolytic and electroless gold plating for electronics applications. The topics covered include developments of non-cyanide electroplating baths for plating soft gold suitable for fabricating microbumps on silicon wafers, electroplating of hard gold and alternative materials with thermally stable electrical contact resistance and wear resistance for use on connectors exposed to elevated temperatures, and neutral, non-cyanide electroless processes for plating pure, soft gold on isolated areas of circuit boards. The development of the new electroless processes has been a subject of great interest and activity, and therefore an extensive survey of the progress in this field is included.
Transcriptional disturbance is implicated in the pathology of polyglutamine diseases, including Huntington's disease (HD). However, it is unknown whether transcriptional repression leads to neuronal death or what forms that death might take. We found transcriptional repression-induced atypical death (TRIAD) of neurons to be distinct from apoptosis, necrosis, or autophagy. The progression of TRIAD was extremely slow in comparison with other types of cell death. Gene expression profiling revealed the reduction of full-length yes-associated protein (YAP), a p73 cofactor to promote apoptosis, as specific to TRIAD. Furthermore, novel neuron-specific YAP isoforms (YAPΔCs) were sustained during TRIAD to suppress neuronal death in a dominant-negative fashion. YAPΔCs and activated p73 were colocalized in the striatal neurons of HD patients and mutant huntingtin (htt) transgenic mice. YAPΔCs also markedly attenuated Htt-induced neuronal death in primary neuron and Drosophila melanogaster models. Collectively, transcriptional repression induces a novel prototype of neuronal death associated with the changes of YAP isoforms and p73, which might be relevant to the HD pathology.
It has been shown that CD1d expression and glycolipid-reactive, CD1d-restricted NKT cells exacerbate the development of obesity and insulin resistance in mice. However, the relevant CD1d-expressing cells that influence the effects of NKT cells on the progression of obesity remain incompletely defined. In this study, we have demonstrated that 3T3-L1 adipocytes can present endogenous ligands to NKT cells, leading to IFN-γ production, which in turn, stimulated 3T3-L1 adipocytes to enhance expression of CD1d and CCL2, and decrease expression of adiponectin. Furthermore, adipocyte-specific CD1d deletion decreased the size of the visceral adipose tissue mass and enhanced insulin sensitivity in mice fed a high-fat diet (HFD). Accordingly, NKT cells were less activated, IFN-γ production was significantly reduced, and levels of adiponectin were increased in these animals as compared with control mice on HFD. Importantly, macrophage recruitment into the adipose tissue of adipocyte-specific CD1d-deficient mice was significantly blunted. These findings indicate that interactions between NKT cells and CD1d-expressing adipocytes producing endogenous NKT cell ligands play a critical role in the induction of inflammation and functional modulation of adipose tissue that leads to obesity.
Aggregation of disease proteins is believed to be a central event in the pathology of polyglutamine diseases, whereas the relationship between aggregation and neuronal death remains controversial. We investigated this question by expressing mutant huntingtin (htt) with a defective adenovirus in different types of neurons prepared from rat cerebral cortex, striatum or cerebellum. The distribution pattern of inclusions is not identical among different types of primary neurons. On day 2 after infection, cytoplasmic inclusions are dominant in cortical and striatal neurons, whereas at day 4 the ratio of nuclear inclusions overtakes that of cytoplasmic inclusions. Meanwhile, nuclear inclusions are always predominantly present in cerebellar neurons. The percentage of inclusion-positive cells is highest in cerebellar neurons, whereas mutant htt induces cell death most remarkably in cortical neurons. As our system uses htt exon 1 protein and thus aggregation occurs independently from cleavage of the full-length htt, our observations indicate that the aggregation process is distinct among different neurons. Most of the neurons containing intracellular (either nuclear or cytoplasmic) aggregates are viable. Our findings suggest that the process of mutant htt aggregation rather than the resulting inclusion body is critical for neuronal cell death.
Ogawa N, Mori A, Hasebe M, Hoshino M, Saito M, Sakamoto K, Nakahara T, Ishii K. Nitric oxide dilates rat retinal blood vessels by cyclooxygenase-dependent mechanisms. Am J Physiol Regul Integr Comp Physiol 297: R968 -R977, 2009. First published July 22, 2009 doi:10.1152/ajpregu.91005.2008.-It has been suggested that nitric oxide (NO) stimulates the cyclooxygenase (COX)-dependent mechanisms in the ocular vasculature; however, the importance of the pathway in regulating retinal circulation in vivo remains to be elucidated. Therefore, we investigated the role of COX-dependent mechanisms in NO-induced vasodilation of retinal blood vessels in thiobutabarbital-anesthetized rats with and without neuronal blockade (tetrodotoxin treatment). Fundus images were captured with a digital camera that was equipped with a special objective lens. The retinal vascular response was assessed by measuring changes in diameter of the retinal blood vessel. The localization of COX and soluble guanylyl cyclase in rat retina was examined using immunohistochemistry. The NO donors (sodium nitroprusside and NOR3) increased the diameter of the retinal blood vessels but decreased systemic blood pressure in a dose-dependent manner. Treatment of rats with indomethacin, a nonselective COX inhibitor, or SC-560, a selective COX-1 inhibitor, markedly attenuated the vasodilation of retinal arterioles, but not the depressor response, to the NO donors. However, both the vascular responses to NO donors were unaffected by the selective COX-2 inhibitors NS-398 and nimesulide. Indomethacin did not change the retinal vascular and depressor responses to hydralazine, 8-(4-chlorophenylthio)-guanosine-3Ј, 5Ј-cyclic monophosphate (a membranepermeable cGMP analog) and 8-(4-chlorophenylthio)-adenosine-3Ј, 5Ј-cyclic monophosphate (a membrane-permeable cAMP analog). Treatment with SQ 22536, an adenylyl cyclase inhibitor, but not ODQ, a soluble guanylyl cyclase inhibitor, significantly attenuated the NOR3-induced vasodilation of retinal arterioles. The COX-1 immunoreactivity was found in retinal blood vessels. The retinal blood vessel was faintly stained for soluble guanylyl cyclase, although the apparent immunoreactivities on mesenteric and choroidal blood vessels were observed. These results suggest that NO exerts a substantial part of its dilatory effect via a mechanism that involves COX-1-dependent pathway in rat retinal vasculature. cyclooxygenases; prostaglandins; retinal blood vessel NITRIC OXIDE (NO) IS A POTENT vasodilator that activates soluble guanylyl cyclase (sGC), resulting in the elevation of intracellular cGMP in vascular smooth muscle cells, thereby dilating blood vessels in many organs (18). However, there is the evidence showing that cGMP-independent alternative/additional pathways are also involved. For example, NO directly activates the Ca 2ϩ
Although elevation of the blood glucose level is a causal adverse effect of treatment with interferon (IFN), the precise underlying molecular mechanism is largely unknown. We examined the effects of type I and type II IFN (IFN- and IFN-␥) on insulin-induced metabolic signaling leading to glucose uptake in 3T3-L1 adipocytes. IFN- suppressed insulininduced tyrosine phosphorylation of IRS-1 without affecting its expression, whereas IFN-␥ reduced both the protein level and tyrosine phosphorylation. Although both IFNs stimulated phosphorylation of STAT1 (at Tyr 701 ) and STAT3 (at Tyr 705 ) after treatment for 30 min, subsequent properties of induction of the SOCS isoform were different. IFN- preferentially induced SOCS1 rather than SOCS3, whereas IFN-␥ strongly induced SOCS3 expression alone. In addition, adenovirus-mediated overexpression of either SOCS1 or SOCS3 inhibited insulin-induced tyrosine phosphorylation of IRS-1, whereas the reduction of IRS-1 protein was observed only in SOCS3-expressed cells. Notably, IFN--induced SOCS1 expression and suppression of insulin-induced tyrosine phosphorylation of IRS-1 were attenuated by siRNA-mediated knockdown of STAT1. In contrast, adenovirusmediated expression of a dominant-negative STAT3 (F-STAT3) attenuated IFN-␥-induced SOCS3 expression, reduction of IRS-1 protein, and suppression of insulin-induced glucose uptake but did not have any effect on the IFN--mediated SOCS1 expression and inhibition of insulin-induced glucose uptake. Interestingly, pretreatment of IFN-␥ with IL-6 synergistically suppressed insulin signaling, even when IL-6 alone had no significant effect. These results indicate that type I and type II IFN induce insulin resistance by inducing distinct SOCS isoforms, and IL-6 synergistically augments IFN-␥-induced insulin resistance by potentiating STAT3-mediated SOCS3 induction in 3T3-L1 adipocytes.
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