人工神经元网络用于复方氯丙嗪的含量测定

将误差反向传播(BP)的人工神经元网络(ANN)模型，用于复方氯丙嗪紫外重叠光谱分 析。对ANN模型的参数进行了优化。采用f(x)二1/(1+e^-x)作为网络节点的输入输出转换函数的三 层神经网络具有较佳性能，当取隐含节点数为15时，该网络预测结果的最小平均相对误差为1.22％， 将研制的ANN模型用于复方氯丙嗪含量测定，其结果与药品标准法和偏最小二乘法(PLs)一致。     

Ly49H signaling through DAP10 is essential for optimal natural killer cell responses to mouse cytomegalovirus infection

The activating natural killer (NK) cell receptor Ly49H recognizes the mouse cytomegalovirus (MCMV) m157 glycoprotein expressed on the surface of infected cells and is required for protection against MCMV. Although Ly49H has previously been shown to signal via DAP12, we now show that Ly49H must also associate with and signal via DAP10 for optimal function. In the absence of DAP12, DAP10 enables Ly49H-mediated killing of m157-bearing target cells, proliferation in response to MCMV infection, and partial protection against MCMV. DAP10-deficient Ly49H⁺ NK cells, expressing only Ly49H–DAP12 receptor complexes, are partially impaired in their ability to proliferate during MCMV infection, display diminished ERK1/2 activation, produce less IFN-γ upon Ly49H engagement, and demonstrate reduced control of MCMV infection. Deletion of both DAP10 and DAP12 completely abrogates Ly49H surface expression and control of MCMV infection. Thus, optimal NK cell–mediated immunity to MCMV depends on Ly49H signaling through both DAP10 and DAP12.NK cells mediate immunity against tumors and pathogens by producing effector cytokines, such as IFN-γ, and by secreting lytic granules that kill target cells. NK cell activation and function are determined by a balance of signals transmitted by inhibitory and activating NK cell receptors (NKRs) (1). Many of the inhibitory NKRs recognize self-ligands such as MHC class Ia, which are recognized by inhibitory Ly49 receptors in mice and inhibitory killer immunoglobulin-like receptors (KIRs) in humans, and MHC class Ib molecules, which are recognized by CD94/NKG2A in both species. Activating NKRs can recognize host-encoded molecules that are induced by transformation or infection of the host cells (e.g., NKG2D ligands), and some activating NKRs recognize non–self-ligands, for example, the mouse CMV (MCMV) m157 glycoprotein, which is recognized by Ly49H (2–6). Activating NKRs typically have short intracellular domains that lack known signaling motifs and instead associate with signaling subunits, including the immunoreceptor tyrosine-based activation motif (ITAM)–bearing CD3-ζ, FcϵRIγ, and DAP12 (also referred to as KARAP) proteins and the YINM motif-containing DAP10 adaptor (7, 8). In the absence of an appropriate signaling subunit, many of the activating NKRs (e.g., NKG2D, CD16, KIR3DS1, and the CD94/NKG2C heterodimer) are not stably expressed on the cell surface (8–11). In humans, some of the activating NKRs, such as CD16, can associate interchangeably with both the ITAM-bearing FcϵRIγ and CD3-ζ subunits for stable expression and signaling (12).DAP12 associates with multiple activating NKRs, including the human and mouse CD94/NKG2C heterodimers, the mouse Ly49H and Ly49D receptors, human NKp44, and the activating human KIR (1). Conversely, NKG2D is the only activating NKR known to associate with DAP10 and initiate NK cell immune responses in vivo (13). Based on the structural similarity of DAP10 and DAP12, particularly within their transmembrane domains, which mediate receptor–adaptor association, it is reasonable to expect that receptors known to associate with DAP12 might also complex with DAP10. However, the alternatively spliced isoform of NKG2D, which is designated NKG2D-S, expressed by activated mouse but not human NK cells, is the only receptor known to pair with both DAP10 and DAP12 in vivo (14–16). Signaling downstream of these adaptors differs as ITAM-containing adaptors recruit Syk or ZAP-70, whereas DAP10 recruits the p85 subunit of PI3 kinase and Grb2 (8, 17–21). NK cells activated via ITAM-containing subunits proliferate, produce cytokines, and are cytotoxic, whereas cells activated through DAP10 are triggered to kill but do not efficiently induce the production of cytokines (14, 15, 19, 22, 23). Importantly, in human NK cells, NKG2D signaling via DAP10 augments IFN-γ and GM-CSF production induced by an activating DAP12-associated KIR; thus, signaling through both adaptors induces a more robust immune response (22).Lack of NK cells renders both humans and mice susceptible to certain infections, particularly the herpesviruses, including human CMVs and MCMVs (24–26). Therefore, experimental infection of mice with MCMV provides an instructive model for studying NK cell responses to viral infection. The Ly49H receptor, which is expressed on a subset of NK cells in C57BL/6 (B6) mice, binds to the m157 glycoprotein encoded by MCMV and is the dominant receptor responsible for NK cell–mediated resistance to MCMV in B6 mice (2, 6, 27–29). Ly49H⁺ NK cells control MCMV replication by both direct cytotoxic mechanisms and by secretion of IFN-γ (30, 31). Genetic ablation of Ly49H, treatment with Ly49H blocking antibody, or infection with a mutant MCMV lacking m157 (Δm157) renders normally resistant B6 mice susceptible to MCMV (32–34). Dokun et al. (35) have reported that early after infection with MCMV, both Ly49H⁺ and Ly49H⁻, NK cells become activated and proliferate, presumably as a result of the proinflammatory cytokine environment. However, by 3 d after infection Ly49H⁺ NK cells preferentially proliferate, and by 6 d the percentage of Ly49H⁺ NK cells increases from ∼50 to 80–90% of the total NK cell population (35). In B6 mice in which the ITAM of DAP12 had been altered to prevent association with Syk or ZAP-70 (designated as DAP12ki or KARAPki mice), this preferential expansion of Ly49H⁺ NK cells was lost (36, 37). Furthermore, these mice exhibited increased viral burden and histopathology (38).Recently, Coudert et al. (39) suggested an association between Ly49H and DAP10 based on transient transfection experiments and coimmunoprecipitation from IL-2–cultured NK cells, and prior studies have suggested an association of mouse SIRP-β1 with DAP10 or DAP12 in a rat mast cell leukemia transfectant model (40). However, it remains unknown whether Ly49H–DAP10 complexes are functionally active and whether they contribute to host protection in vivo. In this paper, we demonstrate that Ly49H associates with DAP10 in addition to DAP12 and that Ly49H–DAP10 complexes are functional and necessary for optimal control of MCMV infection. Deletion of either signaling subunit reduces surface expression of Ly49H, and loss of both DAP10 and DAP12 completely ablates Ly49H surface expression. In the absence of DAP12, Ly49H can signal via DAP10 to induce NK cell responses that partially control MCMV infection. In contrast, the deletion of both DAP10 and DAP12 ablates control of MCMV to the level observed in NK cell–depleted mice. Although either signaling subunit is sufficient for NK cell–mediated killing of m157-bearing targets, we find that DAP10 is necessary for optimal Ly49H-mediated activation of ERK1/2, NK cell proliferation, IFN-γ production, and control of MCMV infection. Thus, Ly49H must associate with both DAP10 and DAP12 to induce optimal NK cell–mediated immunity to MCMV.     

Rate of Clinically Significant Postoperative Pancreatic Fistula in Pancreatic Neuroendocrine Tumors

Background

In 2005, the International Study Group of Pancreatic Fistula (ISGPF) developed a definition and grading system for postoperative pancreatic fistula (POPF). The authors sought to determine the rate of POPF after enucleation and/or resection of pancreatic neuroendocrine tumors (PNET) and to identify clinical, surgical, or pathologic factors associated with POPF.

Methods

A retrospective analysis of pancreatic enucleations and resections performed from March 1998 to April 2010. We defined a clinically significant POPF as a grade B that required nonoperative intervention and grade C.

Results

One hundred twenty-two patients were identified; 62 patients had enucleations and 60 patients had resections of PNET. The rate of clinically significant POPF was 23.7?% (29/122). For pancreatic enucleation, the POPF rate was 27.4?% (17/62, 14 grade B, 3 grade C). The pancreatic resection group had a POPF rate of 20?% (12/60, 10 grade B, 2 grade C). This difference was not significant (p?=?0.4). In univariate analyses, patients in the enucleation group with hereditary syndromes (p?=?0.02) and non-insulinoma tumors (p?=?0.02) had a higher POPF rate. Patients in the resection group with body mass index (BMI)?>?25 (p?p?p?=?0.02) had a higher POPF rate. Multivariate analyses revealed that hereditary syndromes were able to predict POPF in the enucleation group, while having BMI?>?25 and increasing lesion size were also associated with POPF in the group undergoing resection.

Conclusions

We found a clinically significant POPF rate after surgery in PNET to be 23.7?% with no difference by the type of operation. Our POPF rate is comparable to that reported in the literature for pancreatic resection for other types of tumors. Certain inherited genetic diseases—von Hippel–Lindau disease (VHL) and MEN-1—were associated with higher POPF rates.     

Short communication: the number of HIV major NRTI mutations correlates directly with other antiretroviral-associated mutations and indirectly with replicative capacity and reduced drug susceptibility

While it is known that selection for specific HIV-1 drug resistance-associated mutations (DRM) occurs following ART failure, the patterns of resistance mutations, reduced susceptibility (RS), and replicative capacity (RC) that appear as the number of major NRTI mutations increases have been less well-studied. These changes were examined as a function of the number of major NRTI mutations using patient-derived HIV samples submitted for resistance testing between 2003-2005 (n = 35,222) that were grouped by number of NRTI-DRMs present. In the absence of NRTI-DRMs, few (3.4%) samples had RS to one or more NRTI, 33.6% to one or more NNRTI, and 12.6% to one or more PI. With one NRTI-DRM, 94% had RS to one or more NRTI, 50% to one or more NNRTI, and 33% to one or more PI. Increases in NRTI-DRMs were accompanied by increased prevalence of NNRTI and PI DRMs and RS. With one NRTI-DRM, the mean number of NRTIs with RS was 1.7, while when five NRTI-DRMs were present, RS to > or =5 NRTIs was observed. PI-DRM and RS increased at a slower rate than NNRTI-DRM and RS. RC declined from a mean of 97.8% for samples without NRTI-DRMs to 68.9% with one NRTI-DRM, possibly due to reduced fitness conferred by K65R or M184I/V, to an RC of 43.9% for samples with seven to eight NRTI-DRMs. The relatively high percent of samples with NNRTI-DRM but without NRTI-DRMs may result from selection following virologic failure, and/or transmission of virus uniquely resistant to NNRTI.     

Activator of G protein signaling 3 null mice: I. Unexpected alterations in metabolic and cardiovascular function

Activator of G protein signaling (AGS)-3 plays functional roles in cell division, synaptic plasticity, addictive behavior, and neuronal development. As part of a broad effort to define the extent of functional diversity of AGS3-regulated-events in vivo, we generated AGS3 null mice. Surprisingly, AGS3 null adult mice exhibited unexpected alterations in cardiovascular and metabolic functions without any obvious changes in motor skills, basic behavioral traits, and brain morphology. AGS3 null mice exhibited a lean phenotype, reduced fat mass, and increased nocturnal energy expenditure. AGS3 null mice also exhibited altered blood pressure control mechanisms. These studies expand the functional repertoire for AGS3 and other G protein regulatory proteins providing unexpected mechanisms by which G protein systems may be targeted to influence obesity and cardiovascular function.     

Statistical process control charts for ophthalmology

Graefe's Archive for Clinical and Experimental Ophthalmology -