Background Disease-modifying therapies for Alzheimer’s disease (AD) would be most beneficial if applied during the ‘preclinical’ stage (pathology present with cognition intact) before significant neuronal loss occurs. Therefore, biomarkers that can detect AD pathology in its early stages and predict dementia onset and progression will be invaluable for patient care and efficient clinical trial design. Methods 2D–difference gel electrophoresis and liquid chromatography tandem mass spectrometry were used to measure AD-associated changes in cerebrospinal fluid (CSF). Concentrations of CSF YKL-40 were further evaluated by enzyme-linked immunosorbent assay in the discovery cohort (N=47), an independent sample set (N=292) with paired plasma samples (N=237), frontotemporal lobar degeneration (N=9), and progressive supranuclear palsy (PSP, N=6). Human AD brain was studied immunohistochemically to identify potential source(s) of YKL-40. Results In the discovery and validation cohorts, mean CSF YKL-40 was higher in very mild and mild AD-type dementia (Clinical Dementia Rating [CDR] 0.5 and 1) vs. controls (CDR 0) and PSP. Importantly, CSF YKL-40/Aβ42 ratio predicted risk of developing cognitive impairment (CDR 0 to CDR>0 conversion) as well as the best CSF biomarkers identified to date, tau/Aβ42 and p-tau181/Aβ42. Mean plasma YKL-40 was higher in CDR 0.5 and 1 vs. CDR 0 groups, and correlated with CSF levels. YKL-40 immunoreactivity was observed within astrocytes near a subset of amyloid plaques, implicating YKL-40 in the neuroinflammatory response to Aβ deposition. Conclusions These data demonstrate that YKL-40, a putative indicator of neuroinflammation, is elevated in AD, and that, together with Aβ42, has potential prognostic utility as a biomarker for preclinical AD.

Phosphophoryns (PPs), a family of Asp and Ser(P)-rich dentin proteins, are considered to be archetypal regulators of several aspects of extracellular matrix (ECM) biomineralization. We have cloned a rat incisor PP gene, Dmp2, from our odontoblast cDNA library and localized it to mouse chromosome 5q21 within 2 centimorgans of Dmp1, another tooth-specific ECM protein. The phosphophoryns (PPs) 1 (1) are a family of highly phosphorylated proteins with a unique composition and amino acid sequence. Found as the major noncollagenous proteins of the mineralized dentin matrix, the PPs have been considered to be the archetype of macromolecules that might regulate biomineralization processes (2, 3) by binding to the matrix of structural proteins (4), nucleating mineralization (5, 6), and controlling crystal growth (7). To understand how the PPs might carry out these diverse functions, it is crucial to know their amino acid sequences and structures. The PP from various species contain from 35 to 45 residue % aspartic acid and 40 to 55 residue % serine, of which as many as 90% of the Ser residues are phosphorylated (8, 9). The difficulties of Edman sequencing of phosphoserine-rich proteins have limited the information attainable by conventional sequencing efforts (10 -12) to a few internal acidic domains and a short amino-terminal sequence. Recently, chemical sequencing using means to derivatize the phosphoserines has provided a longer NH 2 -terminal sequence (13). Sequencing via cloning of a PP cDNA has also been difficult. A putative PP cDNA was described (14) several years ago, but no sequence data have been reported. Nucleotide probes have generally been unsuccessful because of the high redundancy of the Ser codons (15). Antibody screening of cDNA libraries was not fruitful because of the difficulties of producing high titer PP antibodies (16, 17).We have recently taken a new approach to the production of an antibody to a highly purified, dephosphorylated phosphophoryn (dPP) and, as described below, have been successful in using that antibody to identify several cDNAs in our established rat incisor odontoblast cDNA library (15,18). Sequencing of the clones obtained thus far yielded the expected AspSer-rich composition but, more importantly, revealed both an unexpected, unique "triplet cassette" repeat motif as well as a "doublet" repeat motif. These might account for several of the biomineralization regulatory functions of the phosphophoryns. We report here the nature of these unique sequence blocks. Furthermore, the identification of a PP cDNA clone has allowed the chromosomal localization of the corresponding PP gene. As shown below, the PP gene is colocalized with the gene for a mineralization disorder, dentinogenesis imperfecta, type II, correcting an erroneous assignment (14). EXPERIMENTAL PROCEDURESPP and Antibody Preparation-PP was extracted from rat incisors by the procedure of Rahima and Veis (9). The high M r PP components were isolated by CaCl 2 precipitation from the crude extract, followed by chromatography ...

Resistance exercise is safe and feasible in patients with head and neck cancer receiving radiation; a definitive trial is warranted.

BackgroundIdeally, disease modifying therapies for Alzheimer disease (AD) will be applied during the ‘preclinical’ stage (pathology present with cognition intact) before severe neuronal damage occurs, or upon recognizing very mild cognitive impairment. Developing and judiciously administering such therapies will require biomarker panels to identify early AD pathology, classify disease stage, monitor pathological progression, and predict cognitive decline. To discover such biomarkers, we measured AD-associated changes in the cerebrospinal fluid (CSF) proteome.Methods and FindingsCSF samples from individuals with mild AD (Clinical Dementia Rating [CDR] 1) (n = 24) and cognitively normal controls (CDR 0) (n = 24) were subjected to two-dimensional difference-in-gel electrophoresis. Within 119 differentially-abundant gel features, mass spectrometry (LC-MS/MS) identified 47 proteins. For validation, eleven proteins were re-evaluated by enzyme-linked immunosorbent assays (ELISA). Six of these assays (NrCAM, YKL-40, chromogranin A, carnosinase I, transthyretin, cystatin C) distinguished CDR 1 and CDR 0 groups and were subsequently applied (with tau, p-tau181 and Aβ42 ELISAs) to a larger independent cohort (n = 292) that included individuals with very mild dementia (CDR 0.5). Receiver-operating characteristic curve analyses using stepwise logistic regression yielded optimal biomarker combinations to distinguish CDR 0 from CDR>0 (tau, YKL-40, NrCAM) and CDR 1 from CDR<1 (tau, chromogranin A, carnosinase I) with areas under the curve of 0.90 (0.85–0.94 95% confidence interval [CI]) and 0.88 (0.81–0.94 CI), respectively.ConclusionsFour novel CSF biomarkers for AD (NrCAM, YKL-40, chromogranin A, carnosinase I) can improve the diagnostic accuracy of Aβ42 and tau. Together, these six markers describe six clinicopathological stages from cognitive normalcy to mild dementia, including stages defined by increased risk of cognitive decline. Such a panel might improve clinical trial efficiency by guiding subject enrollment and monitoring disease progression. Further studies will be required to validate this panel and evaluate its potential for distinguishing AD from other dementing conditions.

Few head and neck cancer survivors are participating in any moderate or vigorous exercise, and over half are completely sedentary. Meaningful and potentially beneficial associations between total exercise minutes, QoL, and fatigue were demonstrated. An exercise intervention may have utility in this understudied cancer survivor group. Further research is warranted.

There are several surgical approaches for resection of parapharyngeal space (PPS) neoplasms. The purpose of this study was to evaluate local disease control, facial nerve injury, and need for mandibulotomy associated with resection of PPS neoplasms via the transcervical approach with submandibular gland excision. A retrospective chart review of 33 patients who underwent resection of a PPS neoplasm between October 1991 and July 2000 was performed. Of the 33 patients, 3 patients developed local recurrence after a median follow-up of 24 months. None of the patients experienced facial nerve paresis or paralysis. Three patients (9.1%) required a mandibulotomy for further exposure. This study demonstrated that the transcervical approach with submandibular gland excision for resection of PPS neoplasms provides excellent local disease control with minimal risk of facial nerve injury or need for mandibulotomy and/or tracheotomy.

Standardized, comprehensive platforms for the discovery of protease substrates have been extremely difficult to create. Screens for protease specificity are now frequently based on the cleavage patterns of peptide substrates, which contain small recognition motifs that are required for the cleavage of the scissile bond within an active site. However, these studies do not identify in vivo substrates, nor can they lead to the definition of the macromolecular features that account for the biological specificity of proteases. To use properly folded proteins in a proteomic screen for protease substrates, we used 2D difference gel electrophoresis and tandem MS to identify substrates of an apoptosis-inducing protease, granzyme B. We confirmed the cleavage of procaspase-3, one of the key substrates of this enzyme, and identified several substrates that were previously unknown, as well as the cleavage site for one of these substrates. We were also able to observe the kinetics of substrate cleavage and cleavage product accumulation by using the 2D difference gel electrophoresis methodology. ''Protease proteomics'' may therefore represent an important tool for the discovery of the native substrates of a variety of proteases.

Full-length cDNA coding for dentin matrix protein 1 (DMP1) has been cloned and sequenced, but the corresponding complete protein has not been isolated. In searching for naturally occurring DMP1, we recently discovered that the extracellular matrix of bone contains fragments originating from DMP1. Shortened forms of DMP1, termed 37K and 57K fragments, were treated with alkaline phosphatase and then digested with trypsin. The resultant peptides were purified by a two-dimensional method: size exclusion followed by reversed-phase high performance liquid chromatography. Purified peptides were sequenced by Edman degradation and mass spectrometry, and the sequences compared with the DMP1 sequence predicted from cDNA. Extensive sequencing of tryptic peptides revealed that the 37K fragments originated from the NH 2 -terminal region, and the 57K fragments were from the COOH-terminal part of DMP1. Phosphate analysis indicated that the 37K fragments contained 12 phosphates, and the 57K fragments had 41. From 37K fragments, two peptides lacked a COOH-terminal lysine or arginine; instead they ended at Phe 173