Feasibility of investigating differential proteomic expression in depression: implications for biomarker development in mood disorders

The objective of this study was to determine whether proteomic profiling in serum samples can be utilized in identifying and differentiating mood disorders. A consecutive sample of patients with a confirmed diagnosis of unipolar (UP n=52) or bipolar depression (BP-I n=46, BP-II n=49) and controls (n=141) were recruited. A 7.5-ml blood sample was drawn for proteomic multiplex profiling of 320 proteins utilizing the Myriad RBM Discovery Multi-Analyte Profiling platform. After correcting for multiple testing and adjusting for covariates, growth differentiation factor 15 (GDF-15), hemopexin (HPX), hepsin (HPN), matrix metalloproteinase-7 (MMP-7), retinol-binding protein 4 (RBP-4) and transthyretin (TTR) all showed statistically significant differences among groups. In a series of three post hoc analyses correcting for multiple testing, MMP-7 was significantly different in mood disorder (BP-I+BP-II+UP) vs controls, MMP-7, GDF-15, HPN were significantly different in bipolar cases (BP-I+BP-II) vs controls, and GDF-15, HPX, HPN, RBP-4 and TTR proteins were all significantly different in BP-I vs controls. Good diagnostic accuracy (ROC-AUC⩾0.8) was obtained most notably for GDF-15, RBP-4 and TTR when comparing BP-I vs controls. While based on a small sample not adjusted for medication state, this discovery sample with a conservative method of correction suggests feasibility in using proteomic panels to assist in identifying and distinguishing mood disorders, in particular bipolar I disorder. Replication studies for confirmation, consideration of state vs trait serial assays to delineate proteomic expression of bipolar depression vs previous mania, and utility studies to assess proteomic expression profiling as an advanced decision making tool or companion diagnostic are encouraged.     

Childhood insulinoma masquerading as seizure disorder

A 9 year old girl presented with seizures, weight gain and early morning behavioural changes. She had been commenced on anticonvulsants and was subsequently diagnosed with hyperinsulinaemic hypoglycaemia. This case demonstrates the importance of blood glucose monitoring in children presenting with new‐onset seizures and/or with early morning or fasting behavioural changes, the challenges in localizing the lesion, as well as the difficulties in achieving normoglycaemia prior to, and immediately following, surgery.     

Risk factors and outcomes of cerebrospinal fluid overdrainage in HIV-negative patients with cryptococcal meningitis after the ventriculoperitoneal shunting procedure

Purpose

Shunt procedures used to treat cryptococcal meningitis complicated with hydrocephalus and/or increased intracranial pressure (IICP) could result in cerebrospinal fluid (CSF) overdrainage, thereby presenting therapeutic challenges.

Outcome of respiratory intensive care for the elderly

We followed 1018 patients admitted consecutively to a multidisciplinary respiratory ICU (RICU), with special attention to patients aged 75 yr and over. The elderly had a higher RICU (11/49) and in-hospital (21/49) mortality than younger patients. The 28 survivors of hospitalization had a lower acute physiology score (APS) than nonsurvivors on admission (16.1 +/- 7.8 vs. 21.8 +/- 8.9, respectively), indicating less severe illness. The quality of long-term survival (12 to 24 months) was assessed using an open-ended questionnaire. Eighteen hospital survivors were alive at the time of follow-up and the quality of life was deemed satisfactory by 10 of 13 patients who were living independently. Only two of 28 survivors had been transferred to nursing home care, and two were in acute care hospitals. We conclude most elderly patients discharged from the RICU consider their lifestyle satisfactory and are not a large drain on community health care resources. Further studies of the screening process which determines RICU admission are necessary, because unimodal criteria such as age and APS after admission were not of prognostic value.     

Ia determinants on human T-cell subsets defined by monoclonal antibody. Activation stimuli required for expression

The nature of Ia antigens which appear on human T cells after activation and the stimuli required for their expression was examined utilizing a monoclonal antibody reactive with the Ia antigen framework. T cells were purified using monoclonal antibodies directed either at the entire T-cell population (OKT3) or the T-cell inducer subset (OKT4). By indirect immunofluorescence, it was shown that the human T-cell population contains no detectable Ia+ cells in the resting state. In contrast, in excess of 60% of the T-cell population expresses Ia antigen after alloactivation in the mixed lymphocyte culture. Moreover, these Ia antigens are expressed within both the OKT4+ and OKT4- subsets. Similarly, phytohemagglutinin and concanavalin A induced approximately 20% of peripheral T cells to express Ia antigen and the expression of these antigens is not restricted to either OKT4 subset. In contrast, only the inducer T-cell population which proliferates maximally to soluble antigen expresses Ia antigens after activation by tetanus toxoid. Thus, the expression of human Ia antigens on unique T-cell subsets depends upon the activation stimuli utilized and ability of the individual subset to respond to a given stimulus. Additional studies indicated that Ia antigens appear on previously Ia- T cells after activation and do not result from clonal expansion of a small subset of Ia+ T cells.     

Stromal-mediated protection of tyrosine kinase inhibitor-treated BCR-ABL-expressing leukemia cells

Clinical studies of patients with chronic myeloid leukemia revealed that a common pattern of response is a dramatic fall in the circulating population of blast cells, with a minimal or delayed decrease in marrow blasts, suggesting a protective environment. These observations suggest that a greater understanding of the interaction of stromal cells with leukemic cells is essential. Here, we present an in vivo system for monitoring relative tumor accumulation in leukemic mice and residual disease in leukemic mice treated with a tyrosine kinase inhibitor and an in vitro system for identifying integral factors involved in stromal-mediated cytoprotection. Using the in vivo model, we observed high tumor burden/residual disease in tissues characterized as significant sources of hematopoiesis-promoting stroma, with bone marrow stroma most frequently showing the highest accumulation of leukemia in untreated and nilotinib-treated mice as well as partial protection of leukemic cells from the inhibitory effects of nilotinib. These studies, which showed a pattern of leukemia distribution consistent with what is observed in imatinib- and nilotinib-treated chronic myeloid leukemia patients, were followed by a more in-depth analysis of stroma-leukemia cell interactions that lead to protection of leukemia cells from nilotinib-induced cytotoxicity. For the latter, we used the human BCR-ABL-positive cell line, KU812F, and the human bone marrow stroma cell line, HS-5, to more closely approximate the bone marrow-associated cytoprotection observed in drug-treated leukemia patients. This in vitro system helped to elucidate stromal-secreted viability factors that may play a role in stromal-mediated cytoprotection of tyrosine kinase inhibitor-treated leukemia cells.     

Synthesis and evaluation of (18)F labeled alanine derivatives as potential tumor imaging agents

IntroductionThis paper reports the synthesis and labeling of ¹⁸F alanine derivatives. We also investigate their biological characteristics as potential tumor imaging agents mediated by alanine–serine–cysteine preferring (ASC) transporter system.MethodsThree new ¹⁸F alanine derivatives were prepared from corresponding tosylate-precursors through a two-step labeling reaction. In vitro uptake studies to evaluate and to compare these three analogs were carried out in 9L glioma and PC-3 prostate cancer cell lines. Potential transport mechanisms, protein incorporation and stability of 3-(1-[¹⁸F]fluoromethyl)-L-alanine (L-[¹⁸F]FMA) were investigated in 9L glioma cells. Its biodistribution was determined in a rat-bearing 9L tumor model. PET imaging studies were performed on rat bearing 9L glioma tumors and transgenic mouse carrying spontaneous generated M/tomND tumor (mammary gland adenocarcinoma).ResultsNew ¹⁸F alanine derivatives were prepared with 7%–34% uncorrected radiochemical yields, excellent enantiomeric purity (> 99%) and good radiochemical purity (> 99%). In vitro uptake of the L-[¹⁸F]FMA in 9L glioma and PC-3 prostate cancer cells was higher than that observed for the other two alanine derivatives and [¹⁸F]FDG in the first 1 h. Inhibition of cell uptake studies suggested that L-[¹⁸F]FMA uptake in 9L glioma was predominantly via transport system ASC. After entering into cells, L-[¹⁸F]FMA remained stable and was not incorporated into protein within 2 h. In vivo biodistribution studies demonstrated that L-[¹⁸F]FMA had relatively high uptake in liver and kidney. Tumor uptake was fast, reaching a maximum within 30 min. The tumor-to-muscle, tumor-to-blood and tumor-to-brain ratios at 60 min post injection were 2.2, 1.9 and 3.0, respectively. In PET imaging studies, tumors were visualized with L-[¹⁸F]FMA in both 9L rat and transgenic mouse.ConclusionL-[¹⁸F]FMA showed promising properties as a PET imaging agent for up-regulated ASC transporter associated with tumor proliferation.     

Idiotype-like determinants on human T lymphocytes alloactivated in mixed lymphocyte culture

T cells alloactivated in 5-d MLC with an HLA-DR-different stimulator acquire the capacity of stimulating the autologous mixed lymphocyte response (AMLR). We have demonstrated that activation of AMLR by allosensitized T cells is determined by the expression of the idiotype receptor for the stimulating HLA-DR alloantigen. This has been shown in experiments in which purified, OKT-3-positive T cell suspensions were first primed for 9 d with AMLR-activated T lymphoblasts, then tested in secondary AMLR with autologous lymphoblasts sensitized to various HLA- DR alloantigens. Accelerated memory responses were induced only by autologous lymphoblasts that had been sensitized against the same HLA- DR specificity as the primary AMLR stimulators. This response was not inhibited by a mouse monoclonal antibody recognizing Ia-like determinants, and was not triggered by human allogeneic resting peripheral blood lymphocytes. Thus, recognition of alloactivated T lymphoblasts in secondary AMLR seems to be specific for the idiotype- like determinants expressed by the autologous stimulators.     

Disruption by interferon-alpha of an autocrine interleukin-6 growth loop in IL-6-dependent U266 myeloma cells by homologous and heterologous down-regulation of the IL-6 receptor alpha- and beta-chains.

IL-6 is an autocrine growth factor for U266 myeloma cells and their growth is inhibited by IFN-alpha or IL-6 mAb. We asked, therefore, whether IFN-alpha-induced growth inhibition involved IL-6. IFN-alpha and mAb against IL-6, the IL-6R alpha-(gp80) or beta-chain (gp130) potently inhibited U266 cells. Remarkably, this effect occurred despite IFN-alpha-augmented secretion of endogenous IL-6. However, examining the IL-6R revealed that IFN-alpha drastically curtailed expression of the IL-6R alpha- and beta-chain. This effect occurred on two different levels (protein and mRNA) and by two different mechanisms (directly and indirectly through IL-6). First, IFN-alpha, but not IL-6, greatly decreased gp80 and, to a lesser extent, gp130 mRNA levels which resulted in a loss of IL-6 binding sites. Second, IFN-alpha-induced IL-6 predominantly down-regulated membrane-bound gp130. IFN-alpha-mediated decrease of gp80 levels was not detected on IL-6-independent myeloma (RPMI 8226) or myeloid cells (U937). We conclude that IFN-alpha inhibited IL-6-dependent myeloma cell growth by depriving U266 cells of an essential component of their autocrine growth loop, a functional IL-6R.