Simple mitigation of global depolarizing errors in quantum simulations

To get the best possible results from current quantum devices error mitigation is essential. In this work we present a simple but effective error mitigation technique based on the assumption that noise in a deep quantum circuit is well described by global depolarizing error channels. By measuring the errors directly on the device, we use an error model ansatz to infer error-free results from noisy data. We highlight the effectiveness of our mitigation via two examples of recent interest in quantum many-body physics: entanglement measurements and real-time dynamics of confinement in quantum spin chains. Our technique enables us to get quantitative results from the IBM quantum computers showing signatures of confinement, i.e., we are able to extract the meson masses of the confined excitations which were previously out of reach. Additionally, we show the applicability of this mitigation protocol in a wider setting with numerical simulations of more general tasks using a realistic error model. Our protocol is device-independent, simply implementable, and leads to large improvements in results if the global errors are well described by depolarization.

Small molecule inhibitor of antigen binding and presentation by HLA-DR2b as a therapeutic strategy for the treatment of multiple sclerosis

The strong association of HLA-DR2b (DRB1*1501) with multiple sclerosis (MS) suggests this molecule as prime target for specific immunotherapy. Inhibition of HLA-DR2b-restricted myelin-specific T cells has the potential to selectively prevent CNS pathology mediated by these MHC molecules without undesired global immunosuppression. In this study, we report development of a highly selective small molecule inhibitor of peptide binding and presentation by HLA-DR2b. PV-267, the candidate molecule used in these studies, inhibited cytokine production and proliferation of myelin-specific HLA-DR2b-restricted T cells. PV-267 had no significant effect on T cell responses mediated by other MHC class II molecules, including HLA-DR1, -DR4, or -DR9. Importantly, PV-267 did not induce nonspecific immune activation of human PBMC. Lastly, PV-267 showed treatment efficacy both in preventing experimental autoimmune encephalomyelitis and in treating established disease. The results suggest that blocking the MS-associated HLA-DR2b allele with small molecule inhibitors may be a promising therapeutic strategy for the treatment of MS.

Evaluation of a HLA-DR2 Inhibitor for the Treatment of MS Using Human Cellular Immunologic Models (51.6)

Multiple sclerosis (MS) is the most common human neurological disease affecting approximately 400,000 Americans with no cure available. It is believed to be driven by autoimmune CD4+ T cell responses directed against myelin antigens in the CNS. CD4+ T cell activation and response require antigen presentation by MHC (HLA in human) class II molecules. The HLA class II allele HLA-DRB1*1501 (HLA-DR2) is highly associated with MS, therefore we tested the immunological properties and activity of PV-267, a small molecule DR2 inhibitor in vitro in human cellular immunologic models related to MS using flow cytometry analysis, human cytokine ELISPOT and Bio-Plex assays. In vitro studies of human PBMCs from MS patient or healthy control subjects and testing a myelin basic protein specific T cell line showed that: 1) DR2 inhibitors can inhibit myelin antigen-specific human T cell responses mediated via HLA-DR2; 2) inhibit the production of pro-inflammatory cytokines; 3) treatment with the inhibitors does not have undesired non-specific immune-activating effect on human PBMCs expressing either HLA-DR2 or other HLA-DR molecules. In sum, our preclinical study has established the immunologic efficacy and assessed the safety of DR2 inhibitors in vitro. The results provide a strong rationale for the application of MHC inhibitors for the treatment of MS and potentially other T cell-mediated autoimmune diseases based on the immunological efficacy and good safety profile.

Disruption of protein kinase A localization using a trans-activator of transcription (TAT)-conjugated A-kinase-anchoring peptide reduces cardiac function

Localization of protein kinase A (PKA) via A-kinase-anchoring proteins (AKAPs) is important for cAMP responsiveness in many cellular systems, and evidence suggests that AKAPs play an important role in cardiac signaling. To test the importance of AKAP-mediated targeting of PKA on cardiac function, we designed a cell-permeable peptide, which we termed trans-activator of transcription (TAT)-AKAD for TAT-conjugated A-kinase-anchoring disruptor, using the PKA binding region of AKAP10 and tested the effects of this peptide in isolated cardiac myocytes and in Langendorff-perfused mouse hearts. We initially validated TAT-AKAD as a PKA localization inhibitor in cardiac myocytes by the use of confocal microscopy and cellular fractionation to show that treatment with the peptide disrupts type I and type II PKA regulatory subunits. Knockdown of PKA activity was demonstrated by decrease in phosphorylation of phospholamban and troponin I after beta-adrenergic stimulation in isolated myocytes. Treatment with TAT-AKAD reduced myocyte shortening and rates of contraction and relaxation. Injection of TAT-AKAD (1 microM), but not scrambled control peptide, into the coronary circulation of isolated perfused hearts rapidly (<1 min) and reversibly decreased heart rate and peak left ventricular developed pressure. TAT-AKAD also had a pronounced effect on developed pressure (-dP/dt), consistent with a delayed relaxation of the heart. The effects of TAT-AKAD on heart rate and contractility persisted in hearts pretreated with isoproterenol. Disruption of PKA localization with TAT-AKAD thus had negative effects on chronotropy, inotropy, and lusitropy, thereby indicating a key role for AKAP-targeted PKA in control of heart rate and contractile function.

Carbamate analogues of fumagillin as potent, targeted inhibitors of methionine aminopeptidase-2

Inhibition of methionine aminopeptidase-2 (MetAP2) represents a novel approach to antiangiogenic therapy. We describe the synthesis and activity of fumagillin analogues that address the pharmacokinetic and safety liabilities of earlier candidates in this compound class. Two-step elaboration of fumagillol with amines yielded a diverse series of carbamates at C6 of the cyclohexane spiroepoxide. The most potent of these compounds exhibited subnanomolar inhibition of cell proliferation in HUVEC and BAEC assays. Although a range of functionalities were tolerated at this position, alpha-trisubstituted amines possessed markedly decreased inhibitory activity, and this could be rationalized by modeling based on the known fumagillin-MetAP2 crystal structure. The lead compound resulting from these studies, (3R,4S,5S,6R)-5-methoxy-4-((2R,3R)-2-methyl-3-(3-methylbut-2-enyl)oxiran-2-yl)-1-oxaspiro[2.5]octan-6-yl (R)-1-amino-3-methyl-1-oxobutan-2-ylcarbamate, (PPI-2458), demonstrated an improved pharmacokinetic profile relative to the earlier clinical candidate TNP-470, and has advanced into phase I clinical studies in non-Hodgkin's lymphoma and solid cancers.

Abstract A120: Cellular inhibition of Chk2 kinase and potentiation of camptothecins and radiation by the novel Chk2 inhibitor PV1019

Chk2 is a checkpoint kinase involved in the ATM pathway, which is activated by genomic instability and DNA damage, leading to either cell death (apoptosis) or cell cycle arrest. Chk2 provides an unexplored therapeutic target against cancer cells. We recently reported NSC 109555 as a novel chemotype Chk2 inhibitor. We have now synthesized a derivative of NSC 109555, PV1019 (NSC 744039), which is a selective sub-micromolar inhibitor of Chk2 in vitro. The co-crystal structure of PV1019 bound in the ATP binding pocket of Chk2 confirmed enzymatic/biochemical observations that PV1019 acts as a competitive inhibitor of Chk2 with respect to ATP. PV1019 was found to inhibit Chk2 in cells. It inhibits Chk2 autophosphorylation (which represents the cellular kinase activation of Chk2), Cdc25C phosphorylation, and HDMX degradation in response to DNA damage. PV1019 also protects normal mouse thymocytes against IR-induced apoptosis, and it shows synergistic antiproliferative activity with topotecan, camptothecin, and radiation in human tumor cell lines. We also show that PV1019 as well as Chk2 siRNA can exert antiproliferative activity themselves in the cancer cells with high Chk2 expression in the NCI60 screen. These data indicate that PV1019 is a potent and selective inhibitor of Chk2 with chemotherapeutic and radiosensitization potential.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A120.

Cellular inhibition of checkpoint kinase 2 (Chk2) and potentiation of camptothecins and radiation by the novel Chk2 inhibitor PV1019 [7-nitro-1H-indole-2-carboxylic acid {4-[1-(guanidinohydrazone)-ethyl]-phenyl}-amide]

Chk2 is a checkpoint kinase involved in the ataxia telangiectasia mutated pathway, which is activated by genomic instability and DNA damage, leading to either cell death (apoptosis) or cell cycle arrest. Chk2 provides an unexplored therapeutic target against cancer cells. We recently reported 4,4'-diacetyldiphenylurea-bis(guanylhydrazone) (NSC 109555) as a novel chemotype Chk2 inhibitor. We have now synthesized a derivative of NSC 109555, PV1019 (NSC 744039) [7-nitro-1H-indole-2-carboxylic acid {4-[1-(guanidinohydrazone)-ethyl]-phenyl}-amide], which is a selective submicromolar inhibitor of Chk2 in vitro. The cocrystal structure of PV1019 bound in the ATP binding pocket of Chk2 confirmed enzymatic/biochemical observations that PV1019 acts as a competitive inhibitor of Chk2 with respect to ATP. PV1019 was found to inhibit Chk2 in cells. It inhibits Chk2 autophosphorylation (which represents the cellular kinase activation of Chk2), Cdc25C phosphorylation, and HDMX degradation in response to DNA damage. PV1019 also protects normal mouse thymocytes against ionizing radiation-induced apoptosis, and it shows synergistic antiproliferative activity with topotecan, camptothecin, and radiation in human tumor cell lines. We also show that PV1019 and Chk2 small interfering RNAs can exert antiproliferative activity themselves in the cancer cells with high Chk2 expression in the NCI-60 screen. These data indicate that PV1019 is a potent and selective inhibitor of Chk2 with chemotherapeutic and radiosensitization potential.

Social exclusion in clients with comorbid mental health and substance misuse problems

BACKGROUND

The concept of comorbid mental health problems and substance misuse has gained prominence in the last two decades, due in part to the closure of large psychiatric hospitals and to the increasing prevalence of drug use in the community. This client group has a dual requirement for both medical and social care needs and is at risk for social exclusion.

METHODS

A retrospective matched case-control study to examine aspects of social exclusion between service users who have comorbid diagnoses and those with a single diagnosis. Samples were drawn from the service users of a mental health Trust in the South-East of England, from both Adult Mental Health (n = 400) and Drug and Alcohol services (n = 190). Data were collected from Care Programme Approach assessment forms and medical records. McNemar's chi(2) and odds ratios via a conditional logit regression model are used to test for differences in the social exclusion indicators.

RESULTS

There were significant differences in social exclusion between the comorbid and singly diagnosed clients of the Adult Mental Health service, but differences were less pronounced between the comorbid and singly diagnosed clients of the specialist Drug and Alcohol service.

CONCLUSIONS

Recent Government policy advocates treating comorbid clients within mainstream mental health services. Health care workers need to recognise the likelihood of high levels of social exclusion among clients with comorbid problems.

Defining dual diagnosis of mental illness and substance misuse: some methodological issues

This paper discusses methodological issues arising in the initial stages of a larger epidemiological case-control study. Practitioners from both Generic Mental Health and Substance Misuse Services (n = 170) were asked to identify which of their clients, from a time-limited caseload (n = 2341), had comorbid mental health and substance misuse problems. Although practitioners were provided with a definition of 'singly diagnosed' and 'dually diagnosed', it became apparent that these definitions were applied pragmatically, depending on the nature of the client's primary problem and the agency they were presenting to. Issues raised include the time period in which a client was considered to have a concurrent mental health problem and substance misuse, how a 'mental health problem' was defined and whether a personality disorder should be categorized as a 'mental health problem'. There was also some disagreement about whether clients who were being treated primarily by Substance Misuse Services, but were also taking prescribed antidepressants, implicitly had a 'mental health problem'. We raise these methodological issues, as they have implications for determining the prevalence of 'dual diagnosis' and the subsequent provision of services.

Corticotropin-releasing hormone binding to the syncytiotrophoblast membranes

The human placenta secretes large amounts of corticotropin-releasing hormone (CRH) which was thought to exert a paracrine action in the placenta. We have recently characterized high-affinity binding sites for CRH in the human placenta. However, our studies utilized whole placental membranes, which did not identify the site of binding of CRH in the plasma membrane. In this study we investigated the characteristics of CRH binding to purified mother-facing, brush border membranes (BBM) and fetus-facing, basal plasma membranes (BPM) of the syncytiotrophoblast. The two membranes were separated by a series of differential and density-gradient centrifugations. The purity of the membranes was determined by measuring alkaline phosphatase, as a marker of BBM and Na+/K+ATPase as a marker of BPM. Each membrane showed specific and high-affinity binding. Scatchard analysis revealed a high-affinity binding site for CRH with Kd of 1.0 +/- 0.15 and 1.3 +/- 0.176 for BBM and BPM, respectively. The maximal number of binding sites was significantly different (P < 0.01) in the two plasma membranes: Bmax of 79 +/- 6.4 fmol/mg protein for BBM and 23 +/- 3.9 fmol/mg protein for BPM. Both the mother-facing and fetus-facing membranes of the syncytiotrophoblast contain binding proteins for CRH, with significantly more binding sites on the mother-facing membranes. The functional consequences of CRH binding could be different for the two polar membranes due to differential localization of second messenger systems between the two membrane types. It is proposed that partial purification of BBM and BPM provides a better system to study CRH action in the placenta, than whole placental membrane preparations.

Beta2-agonists prevent Th1 development by selective inhibition of interleukin 12

Interleukin 12 (IL-12) plays a central role in the immune system by skewing the immune response towards T helper 1 (Th1) type responses which are characterized by high interferon-gamma and low IL-4 production. In this report we present evidence that beta2-agonists inhibit IL-12 production by both human monocytes in response to lipopolysaccharide (LPS) and dendritic cells stimulated via CD40. Inhibition of IL-12 production is selective, as other cytokines produced by monocytes are unaffected. IL-12 inhibition is dependent on beta2-adrenoceptor stimulation and correlates with increased levels of intracellular cAMP. In conjunction with their ability to suppress IL-12 production, when beta2-agonists are added at priming of neonatal T lymphocytes, they inhibit the development of Th1-type cells, while promoting T helper 2 (Th2) cell differentiation. Further, the in vivo administration of a therapeutic dose of salbutamol results in the selective inhibition of IL-12 production by whole blood lymphocytes stimulated in vitro with LPS. These findings provide new insight into the immunological consequences of the clinical use of beta2-agonists and may suggest new approaches for the treatment of Th1-mediated diseases.

A low pH enzyme linked immunoassay using two monoclonal antibodies for the serological detection and monitoring of breast cancer

A new, simple and sensitive low pH ELISA method has been developed to measure serum levels of tumour associated antigens detectable by monoclonal antibodies HMFG1 and HMFG2. We examined sera from healthy controls, patients with neoplastic and non-neoplastic conditions of breast, liver and gastrointestinal tract. The majority of patients with metastatic breast cancer had elevated serum antigens (69% HMFG1, 72% HMFG2) compared to healthy controls (6.3% HMFG1, 3.0% HMFG2) or patients with benign breast disease (17% HMFG1, 4% HMFG2). There was no discrimination using these assays between patients with neoplastic and non-neoplastic conditions of liver and gastrointestinal tract. This new method promises to be of value in the assessment and management of patients with breast cancer.

A new immunoassay using monoclonal antibodies HMFG1 and HMFG2 together with an existing marker CA125 for the serological detection and management of epithelial ovarian cancer

A new method with a low pH step to dissociate serum complexes has been developed to measure serum levels of antigens associated with ovarian cancer. The antigens are detected by monoclonal antibodies HMFG1 and HMFG2 and have been compared to an existing ovarian cancer associated antigen detected by the antibody CA125. Elevated HMFG1 was found in 56%, and elevated HMFG2 in 65% of 924 sera from 85 patients with ovarian cancer. CA125 was elevated in 85% of these sera. When the three markers were used in conjunction, 95% of sera from patients with ovarian cancer were positive--compared with 7% in sera from healthy control subjects. Therefore, the combination of HMFG1, HMFG2 and CA125 increases the diagnostic accuracy. If all three markers are normal in a patient previously treated for ovarian cancer then no further positive information regarding disease status can be obtained by ultrasound and CT scanning.