pH-responsive fluorescence chemical sensor constituted by conjugated polymers containing pyridine rings.

Poly(p-pyridinium phenylene ethynylene)s (PPyPE) functionalized with alternating donor-acceptor repeat units were synthesized by a Pd-catalyzed Sonogashira coupling reaction between diethynyl monomer and di-iodopyridine for use as a pH-responsive fluorescence chemical sensor. The synthesized PPyPE, containing pyridine units, was characterized by FT-IR, (1)H and (13)C NMR, UV-visible and fluorescence spectroscopies. We investigated the relationship between changes of optical properties and protonation/deprotonation of PPyPE containing pyridine units in solution. Addition of HCl decreased and red-shifted the fluorescence intensity of the conjugated polymers that contained pyridine rings; fluorescence intensity of the polymers increased upon addition of NaOH solution. The synthesized PPyPE was found to be an effective and reusable chemical sensor for pH sensing.

Associations between brain-derived neurotrophic factor and estradiol in women's saliva.

OBJECTIVE: The aim of this study was to assess the relationship between brain-derived neurotrophic factor (BDNF) and sex hormones (estradiol [E2] and progesterone), using saliva samples obtained from healthy women. METHODS: Forty female dental hygienist students were divided into groups according to being in the follicular phase or luteal phase. Saliva BDNF, E2, and progesterone levels were measured using a sandwich ELISA system. The correlation between these factors was analyzed using Spearman's index, and fluctuations of these levels in the whole menstrual cycle were investigated classifying the subjects by every 4 days according to the phase of their menstrual cycle. RESULTS: Saliva BDNF variations strongly correlated with saliva E2 levels in the follicular phase (r = 0.721, p = 0.000) and luteal phase (r = 0.770, p = 0.000). The correlation coefficient showing the relationship between progesterone and BDNF levels in the luteal phase (r = 0.371, p = 0.157) was lower than that in the follicular phase (r = 0.631, p = 0.001). Moreover, the fluctuation of BDNF levels in the menstrual cycle followed a similar pattern to that of E2. CONCLUSIONS: We found that saliva BDNF and E2 levels were closely related in healthy young women. In particular, for first time, that correlation was investigated throughout the menstrual cycle. Monitoring of saliva BDNF may yield insight into women's reproductive and mental health.

Effects of ionic substances on the adsorption of egg white proteins to a stainless steel surface.

The surface fouling of food processing equipment by proteins was studied by investigating the adsorption of egg white proteins to the surface of stainless steel (SS) at pH 7.4 and 30 °C, and particularly the effects of different types of ionic substances. Ovalbumin and ovomucoid, acidic egg white proteins, were less adsorbed in the presence of phosphate (P(i)), a multivalent anion, than in the presence of HEPES, an amphoteric ion. On the other hand, lysozyme, a basic egg white protein, was more adsorbed in the presence of P(i) than in the presence of HEPES. Citrate as another multivalent anion and taurine as another amphoteric ion affected the respective adsorption of those egg white proteins similarly to P(i) and HEPES. The adsorption of an egg white protein to an SS surface therefore depended on the combination of the type of protein and the effective charge of the coexisting ionic substance. This behaviour can be well explained by assuming that a small ionic substance precedes a protein in attaching to an SS surface, resulting in an alteration to the effective surface charge. Pretreating SS with a P(i) buffer lowered the amount of ovalbumin adsorbed with the HEPES buffer, demonstrating that P(i) can attach to and remain on the SS surface to affect the subsequent protein adsorption.

Changes in urinary bone resorption markers (pyridinoline, deoxypyridinoline) resulting from experimentally-induced osteoarthritis in the temporomandibular joint of rats.

The purpose of this study was to quantify the urinary bone resorption markers, pyridinoline (Pyr) and deoxypyridinoline (Dpyr), excreted from experimentally-induced osteoarthritis (OA) in the temporomandibular joint (TMJ) of rats. Osteoarthritic lesions were induced by intra-articular injection of collagenase into the right TMJs of 16-week-old male rats. The whole day's urine was collected from each animal one day before the injection and 5, 7, 11 and 14 days after the injection. Urine samples were analyzed by high-perfomance liquid chromatography and fluorescence spectroscopy. Histological changes in condyle were examined by using paraffin sections with toluidine blue staining. Degenerative changes were observed in the articular cartilage of the experimental group on day 7 and day 14 after the injection of collagenase. The concentration of Pyr was remarkably high in the experimental group, and consequently the Pyr to Dpyr ratio was significantly higher (p<0.05) in the experimental group than in the control group from 7-14 days after the injection. These findings suggest that a urinary Pyr/Dpyr ratio would be available for the detection of degenerative changes in condyle relevant to temporomandibular joint osteoarthritis (TMJ OA).

Effects of sutural distraction osteogenesis applied to rat maxillary complex on craniofacial growth.

PURPOSE: This study was designed to investigate the effects of artificial mechanical separation of the circummaxillary sutures on craniofacial growth in growing rats. MATERIALS AND METHODS: Twenty 4-week-old Wistar strain male rats were divided equally into experimental and control groups. In the experimental group, 4 holes were made on the maxillary and temporary bones, and expansion appliances were placed into the holes for sutural separation bilaterally. The operated control group underwent sham surgery only. Lateral and dorsoventral cephalograms were taken of the animals every 2 weeks from age 4 to 12 weeks. Linear and angular measurements on the lateral cephalograms were analyzed and subjected to statistical treatment with Student's t-test. All animals were killed for histologic examination 8 weeks after the initiation of the experiment. RESULTS: Nasomaxillary growth and the forward displacement were significantly larger in the experimental group than in the controls (P <.01). New bone formation was clearly observed in the (mechanically separated) sutural space in association with normal healing of the sutural structures. CONCLUSIONS: These findings show that mechanical separation of the circummaxillary sutures, as a new orthopedic approach, accelerated nasomaxillary growth, in this experimental model.

Immunohistochemical study of matrilin-1 in arthritic articular cartilage of the mandibular condyle.

BACKGROUND: The objective of this study was to investigate the expression of matrilin-1 in arthritic articular cartilage of the mandibular condyle by means of immunohistochemical methods. METHODS: Condylar cartilage specimens were obtained from temporomandibular joints (TMJs) of 12 patients with arthritis (osteoarthritis and internal derangement) (mean age 51.8 years; age range 28-71 years) and four patients with TMJ ankylosis (mean age 44.0 years; age range 16-64 years), diagnosed clinically and with imaging examinations. Paraffin sections were immunostained with anti-matrilin-1 antibodies. RESULTS: Matrilin-1 expression was detected in both patient groups with TMJ ankylosis and arthritis, and the level was remarkably higher in arthritic cartilage. The mean percentage of matrilin-1-producing cells to the total chondrocytes was significantly (P < 0.05) greater in the arthritic group (43.9 +/- 19.2%) than in subjects with TMJ ankylosis (28.0 +/- 8.7%). CONCLUSIONS: Articular chondrocytes in the TMJ condyle can express matrilin-1 and the expression is enhanced in arthritic cartilage, suggesting a presence of functional or adaptive remodeling in the condyle in response to degenerative changes in the TMJ structures.