Abstract. In the recent past, evidence is increasing indicating the existence of a subpopulation of resistant tumor cells in head and neck squamous cell carcinoma (Hnscc) that cannot be eradicated by established antineoplastic treatments. these cancer stem cells (cscs) have features of somatic stem cells such as selfrenewal, proliferation and differentiation. cD44 + cells in tumors of the head and neck are referred to as cscs of Hnscc. expression profiling of cD44 in 29 HNSCC tumors was performed by fluorescence microscopy. elIsA analysis was performed to detect concentration of soluble cD44 in the peripheral blood of 29 Hnscc patients and 11 healthy controls. expression of cD44 was determined in all Hnscc tissue samples (n=29). In all samples a surface staining pattern was found. the concentration of cD44 in the peripheral blood of HNSCC patients was significantly higher compared to a healthy control group (m Hnscc =13.5±0.5 ng/ ml; m cont =9.3±0.6 ng/ml; p=0.6x10 -12 ). the role of cD44 as a marker for cscs in Hnscc remains to be ascertained. Further experiments might reveal its role as a diagnostic and prognostic factor, and possibly as a therapeutic target.

Even though sudden sensorineural hearing loss (SHL) is a quite frequent disease, the pathogenetic processes leading to it are widely unknown. There is increasing evidence that immunomodulatory cells, especially T lymphocytes, might be involved. Twelve patients with acute SHL and 12 healthy, age-matched individuals were included in this study. In addition to routine blood parameters, plasma levels of tumor necrosis factor alpha (TNF-α), soluble CD40 (sCD40) and sCD40 ligand (sCD40L) were determined by ELISA. Moreover, peripheral blood mononuclear cells were isolated by Ficoll density gradient. Afterwards, in subpopulations – identified by CD14 (monocytes), CD68 (macrophages), CD3 (T lymphocytes) or CD19 (B lymphocytes) immunoreactivity – proinflammatory (CD40, TNF-α or cyclooxygenase-2) and proadhesive (CD38) proteins were measured by 2-color fluorescence-activated cell sorter analyses. In comparison with healthy individuals, patients with acute SHL revealed elevated plasma levels of sCD40 and sCD40L and a significantly decreased percentage (36%) of lymphocytes, especially of T lymphocytes (28%). Additionally, in patients with acute SHL the percentage of proinflammatory CD40, TNF-α, cyclooxygenase-2 or CD38-positive T or B lymphocytes was significantly increased. Our data suggest an enhanced extravasation of proadhesive and proinflammatory lymphocytes from the peripheral circulation, which may contribute to SHL disease induction as well as progression and, thus, may be suggested as a novel therapeutical target.

Cerebrospinal fluid (CSF) biomarkers play an important role in the differential diagnosis of neurodegenerative diseases such as Alzheimer’s disease (AD) and its postulated precursor stage mild cognitive impairment (MCI). While CSF tau protein, phospho-tau protein and β-amyloid have become part of the diagnostic process in clinical routine, the importance of several other biomarkers remains quite unclear. Among these, amino acids and metabolic compounds have been studied in clinical conditions mostly other than AD and, to our knowledge, never in MCI. In patients with AD (n = 14) and MCI (n = 13) we now determined CSF levels of 36 different amino acids and metabolic compounds by high-performance liquid chromatography. We found that 8 out of 36 amino acids (urea, threonine, glutamate, citrulline, α-aminobutyric acid, ornithine, ammonia and arginine) were significantly elevated in the CSF of patients with AD compared to those with MCI. As most of these amino acids and metabolic compounds are functionally important for brain-specific metabolic processes, neurotransmitter pathways or compensatory mechanisms, our findings might reflect these changes occurring within the brain of patients with MCI and those who developed manifest AD.