Repair of cartilage defects with devitalized osteochondral tissue: A pilot animal study.

Devitalization using high hydrostatic pressure (HHP) treatment inactivates cells while matrix structure and biomechanical properties are maintained. Because of strong chondroinductive potential of HHP-devitalized cartilage matrix, it may be used as scaffold for reconstruction of (osteo-)chondral lesions. In this pilot study, we evaluated the feasibility of HHP-devitalized osteochondral tissue to repair osteochondral defects in a rabbit model. Removal and reimplantation of osteochondral plugs were performed in 12 female New Zealand White rabbits. From the knee joint of each animal, osteochondral plugs (diameter = 4 mm; depth = 2.5 mm) were harvested and devitalized by HHP (452 MPa for 10 min). Afterward, the plugs were reimplanted into the respective cavity, from where they were taken. Animals were sacrificed 12 weeks postoperatively and the integration of osteochondral plugs was examined using µ-CT, MRI, and histological staining. Furthermore, revitalization of HHP-treated osteochondral plugs was characterized by gene expression analyses. Macroscopic evaluation of tissue repair at implantation sites of HHP-treated osteochondral plugs showed an adequate defect filling 12 weeks after implantation. Plug margins were hardly detectable indicating successful tissue integration. Additionally, gene expression analyses demonstrated initial revitalization of the HHP-treated tissue 12 weeks postoperatively. Our preliminary data revealed that HHP-treated osteochondral plugs could be used to refill osteochondral defects in the knee joint and promote cell migration into defect site. Data indicated that HHP-treated tissue has the potential to act as functional scaffolds for reconstruction of cartilage defects. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2354-2364, 2019.

Gene expression profiling of circulating natural killer cells in head and neck squamous cell carcinoma.

BACKGROUND: Natural killer (NK) cells are a major player of the innate immune system. Besides known risk factors for head and neck squamous cell carcinoma (HNSCC), impaired immune surveillance may as well lead to tumor manifestation. MATERIALS AND METHODS: In the present study, microarrays technologies were employed in order to perform gene expression profiling of NK cells in HNSCC patients. Differentially expressed genes have been detected in a comparative setting consisting of non-treated HNSCC patients, treated recurrence-free HNSCC patients and healthy control subjects. RESULTS: Cytokine receptors such as CCR7, IL-7R, and CXCR3 were down-regulated in non-treated HNSCC patients compared to healthy subjects, indicating impaired immune surveillance. In treated patients, up-regulated genes such as receptors for Fc fragments of specific antibodies, or ficolin-1 can be withheld as an immunological response to tumor manifestation. CONCLUSION: This study provides insights into gene expression changes in NK cells of HNSCC dependent upon clinical status and introduces several candidate genes suitable for further investigation.

Distribution of circulating natural killer cells and T lymphocytes in head and neck squamous cell carcinoma.

OBJECTIVE: Natural killer (NK) cells are capable of eliminating malignantly transformed cells without prior sensitization. In contrast to NK-cells, T lymphocytes possess antitumourous activity that is restricted to major histocompatibility complex (MHC) recognition. The aim of this study was to determine the causes of the different distributions of these cell types in the peripheral blood of patients with head and neck squamous cell carcinomas (HNSCC). METHODS: A cohort of 105 subjects was divided into three clinical groups: non-treated HNSCC patients, treated relapse-free HNSCC patients and healthy control subjects. Peripheral blood mononuclear cells (PBMC) were isolated from venous blood, subsets were depleted, flow cytometric counts were made and subsequently correlation analyses with clinical parameters were performed. RESULTS: Treated relapse-free HNSCC patients have a significantly increased mean proportion of NK-cells in PBMC of 26.39% (p<0.001), whereas T lymphocytes and natural killer-T-(NKT) cells of treated patients have a significantly decreased mean proportion in PBMC of 55.15% (p<0.05) at least 12 months after treatment. This inverse redistribution of these two subsets is reflected in a significantly increased mean NK/T-ratio of 0.54 (p<0.05) in treated patients. The NK/T-ratio correlates with the systemic invasiveness of the type of therapy patients undergo and is highest after surgery with adjuvant radiochemotherapy (0.64, rs=0.334, p<0.01). This appears to be a post-therapeutic long-term effect in treated patients, as they had a mean relapse-free period until venous puncture of 47.9 months in our study. We also demonstrated age-dependent changes in the peripheral distribution of T- and NK-cells. CONCLUSION: These findings reveal new aspects in understanding tumour biology and interactions with the cellular immune system which provide novel starting points for further research.

Effects of high hydrostatic pressure on bacterial growth on human ossicles explanted from cholesteatoma patients.

BACKGROUND: High hydrostatic pressure (HHP) treatment can eliminate cholesteatoma cells from explanted human ossicles prior to re-insertion. We analyzed the effects of HHP treatment on the microbial flora on ossicles and on the planktonic and biofilm states of selected isolates. METHODOLOGY: Twenty-six ossicles were explanted from cholesteatoma patients. Five ossicles were directly analyzed for microbial growth without further treatment. Fifteen ossicles were cut into two pieces. One piece was exposed to HHP of 350 MPa for 10 minutes. Both the treated and untreated (control) pieces were then assessed semi-quantitatively. Three ossicles were cut into two pieces and exposed to identical pressure conditions with or without the addition of one of two different combinations of antibiotics to the medium. Differential effects of 10-minute in vitro exposure of planktonic and biofilm bacteria to pressures of 100 MPa, 250 MPa, 400 MPa and 540 MPa in isotonic and hypotonic media were analyzed using two patient isolates of Staphylococcus epidermidis and Neisseria subflava. Bacterial cell inactivation and biofilm destruction were assessed by colony counting and electron microscopy. PRINCIPAL FINDINGS: A variety of microorganisms were isolated from the ossicles. Irrespective of the medium, HHP treatment at 350 MPa for 10 minutes led to satisfying but incomplete inactivation especially of gram-negative bacteria. The addition of antibiotics increased the efficacy of elimination. A comparison of HHP treatment of planktonic and biofilm cells showed that the effects of HPP were reduced by about one decadic logarithmic unit when HPP was applied to biofilms. High hydrostatic pressure conditions that are suitable to inactivate cholesteatoma cells fail to completely sterilize ossicles even if antibiotics are added. As a result of the reduced microbial load and the viability loss of surviving bacteria, however, there is a lower risk of re-infection after re-insertion.

Normative data for a solution-based taste test.

The aim of our study was to study gustatory function in a large portion of the general population using liquid tastants, extending previous research. Further, we investigated the test-retest reliability of the test used. Data from 944 healthy subjects were used (498 women and 446 men, mean age 45 years; age range 5-90 years). For lateralized assessment of gustatory function, liquid taste solutions were used with different concentrations of each tastant (sweet 0.03, 0.1, 0.4, 2 g/mL sucrose solution; sour 0.01, 0.05, 0.1, 0.15 mL citric acid; salty 0.025, 0.075, 0.15, 0.36 mL sodium chloride solution; bitter 0.0002, 0.0005, 0.001, 0.01 mL quinine hydrochloride). A drop (approximately 20 µL) of liquid tastant was applied on the right side or on the left side of the anterior/posterior third of the extended tongue. The taste test had a good test-retest reliability r (304) = 0.78 (P < 0.001) for the total score and r (304) = 0.77 (P < 0.001) for the right-sided measures and r (304) = 0.75 (P < 0.001) for the left-sided measures, respectively. Gustatory sensitivity was found to decrease with age; women were more sensitive to gustatory stimuli than men. Irrespective of the sex-related differences, the total score at the 10th percentile was 28 in subjects younger than 15 years, 26.1 for ages from 16 to 35 years, 25 for ages from 36 to 55 years, and 24 for subjects older than 56 years of age. In conclusion, this test is recommended for clinical assessment of the ability to taste. The test provides reliable data, which is easy to handle, inexpensive, timesaving and can be self-made.