Inhibition of circulating dipeptidyl peptidase 4 activity in patients with metastatic prostate cancer.

Cancer is responsible for many deaths and is a major source of healthcare expenditures. The identification of new, non-invasive biomarkers might allow improvement of the direct diagnostic or prognostic ability of already available tools. Here, we took the innovative approach of interrogating the activity of exopeptidases in the serum of cancer patients with the aim of establishing a distinction based on enzymatic function, instead of simple protein levels, as a means to biomarker discovery.

Serum 25-hydroxyvitamin D deficiency; a risk factor for chronic kidney disease in ambulatory indigent patients.

Objective: To assess whether 25-hydroxyvitamin D (25[OH]D) deficiency is a risk factor for chronic kidney disease (CKD) in ambulatory indigent patients.

Methods: Data for all serum 25(OH)D concentrations measured during 2010 in our ambulatory nondialysis-dependent patients were analyzed along with CKD-related parameters. Patients were stratified into groups based on 25(OH)D levels of <10, 10 to 19, 20 to 29, and ≥30 ng/mL.

Vitamin D deficiency in urban indigent patients in Southern California.

Objective: To determine the prevalence of 25-hydroxy (OH) vitamin D deficiency in ambulatory and hospitalized patients from a large urban county medical center in Southern California, and assess the effects of season, ethnicity, age, location of care, and comorbidities on prevalence.

Methods: Data for all serum 25(OH)-D2 and -D3 concentrations measured during 2010, along with associated demographic characteristics and comorbidity data, were analyzed. 25(OH) D concentrations were measured using liquid chromatography-tandem mass spectrometry.

A sequence-specific exopeptidase activity test (SSEAT) for "functional" biomarker discovery.

One form of functional proteomics entails profiling of genuine activities, as opposed to surrogates of activity or active "states," in a complex biological matrix: for example, tracking enzyme-catalyzed changes, in real time, ranging from simple modifications to complex anabolic or catabolic reactions. Here we present a test to compare defined exoprotease activities within individual proteomes of two or more groups of biological samples. It tracks degradation of artificial substrates, under strictly controlled conditions, using semiautomated MALDI-TOF mass spectrometric analysis of the resulting patterns.

Retinoylserine and retinoylalanine, natural products of the moth Trichoplusia ni.

Insect cells convert vitamin A into a number of retinoids that are evolutionarily conserved with those of mammalian cells. However, insect cells also produce additional natural retinoids. Namely, two retinoic acid peptides, N-trans-retinoylserine (1) and N-trans-retinoylalanine (2), have been isolated from a cell line of the common cabbage looper, Trichoplusia ni.

Comparison of antigen constructs and carrier molecules for augmenting the immunogenicity of the monosaccharide epithelial cancer antigen Tn.

We have demonstrated previously that the optimal method for inducing an antibody response against defined cancer antigens is covalent conjugation of the antigen to keyhole limpet hemocyanin (KLH) and use of the potent saponin adjuvant QS-21. Single molecules of glycolipids (tetrasaccharides, pentasaccharides, or hexasaccharides) and MUC1 peptides (containing between one and five MUC1 tandem repeats) conjugated to KLH have proven sufficient for antibody recognition and vaccine construction. However, cancer specificity of monoclonal antibodies against the monosaccharide Tn and disaccharide sTn comes largely from recognition of clusters (c) of these molecules on the cell surface.

Comparison of antibody titers after immunization with monovalent or tetravalent KLH conjugate vaccines.

Antigens such as ganglioside GD3, neutral glycolipid Lewis(y) (Le(y)) and mucins MUC1 and MUC2 are over-expressed on the cell surface of many tumors. We have shown previously that conjugation of antigens such as these to keyhole limpet hemocyanin (KLH) and the use of immunological adjuvant QS-21 is the optimal approach for inducing high titer IgM and IgG antibodies. These antibodies are able to bind with natural antigens on the tumor cell surface and mediate complement dependent cytotoxicity and/or antibody dependent cell mediated cytotoxicity.