Background: HDC catalyzes the rate-limiting step in histamine biosynthesis. Results: A mutation based on the crystal structure of HDC changed the substrate selectivity from L-histidine to L-DOPA. Conclusion: The molecular basis for substrate specificity and recognition of group II PLP-dependent decarboxylases were clarified. Significance: Knowledge of the HDC tertiary structure now makes it possible to design novel drugs that prevent histamine biosynthesis.

Manuka honey, obtained from Leptospermum scoparium flowers in New Zealand, has strong antibacterial properties. In this study, plausible authentication of the manuka honey was inspected by measuring leptosperin, methyl syringate 4-O-β-D-gentiobiose, along with methyl syringate. Despite a gradual decrease in methyl syringate content over 30 days at 50 °C, even at moderate 37 °C, leptosperin remained stable. A considerable correlation between nonperoxide antibacterial activity and leptosperin content was observed in 20 certified manuka honey samples. Leptosperin and methyl syringate in manuka honey and related products were analyzed using HPLC connected with mass spectrometry. One noncertified brand displayed significant variations in the leptosperin and methyl syringate contents between two samples obtained from different regions. Therefore, certification is clearly required to protect consumers from disguised and/or low-quality honey. Because leptosperin is stable during storage and specific to manuka honey, its measurement may be applicable for manuka honey authentication.

BackgroundThere is no confirmed strategy for treating painful bladder syndrome/interstitial cystitis (PBS/IC) with unclear etiology. Therefore, a pilot study was carried out to evaluate the efficacy and safety of hyperbaric oxygen (HBO) therapy in treatment-resistant PBS/IC patients.MethodsHBO treatment (2.0 ATA for 60 minutes/day × 5 days/week for 2 or 4 weeks) was performed on 11 patients with severe symptoms that had not been improved by previous therapy regimens between December 2004 and July 2009.ResultsSeven of the 11 patients demonstrated persistent improvement in symptoms during the 12 months after HBO treatment. These responders demonstrated a decrease in the pelvic pain scale and urgency scale from 7.7 ± 1.0 and, 6.6 ± 0.9 to 3.4 ± 2.5 and 4.3 ± 2.4 after 12 months, respectively (p < 0.05). The total score of the interstitial cystitis symptom index and 24-hour urinary frequency demonstrated a significant sustained decrease from the baseline. Two responders, who received an additional course of HBO 12 and 13 months after initial treatment, respectively, did not suffer impairment for more than two years. There was one case of transient eustachian tube dysfunction and three cases of reversible exudative otitis media as a consequence of HBO treatment.ConclusionsHBO is a potent treatment for PBS/IC patients resistant to conventional therapy. It was well tolerated and provided maintained amelioration of pain, urgency and urinary frequency for at least 12 months.

It is necessary to control the rheological properties of bolus to prevent aspiration. To know the risk of aspiration for each person with difficulty in mastication and swallowing, it will be effective to use a test fluid which enables doctors to judge the safe range of the viscosity based on videofluorography. Since the knowledge of dominant factors which govern rheology is required, effects of shear rate, cooling rate, concentration of polysaccharides, coexisting seasonings on viscosity and viscoelasticity are overviewed. Since chemical senses are also known to affect the swallowing behavior, the relation between texture and flavor release is described briefly. Mixture of polysaccharides, proteins and fluid gels are overviewed as texture modifiers. Acoustic analysis of swallowing, extrusion method, a falling needle viscometer, tribological study on frictional coefficient of bolus are also described as each method is expected to be a useful tool to understand the complicated aspect of the disorder in mastication and deglutition. Mastication and swallowing of minced foods and model food gels are also described. Finally, the importance of the communication and collaboration between different disciplines is emphasized. Practical Applications Polysaccharides have been used to modify the texture of foods. It is necessary to know how these polysaccharides influence the swallowing behavior to design foods for elderly. Since the texture of foods is influenced by taste, aroma and conversely these are influenced by texture, the knowledge on the relation between texture and flavor release is crucial to manipulate the foods to reduce the risk of aspiration. Some examples which are expected to be helpful to design foods for elderly are shown.

The gelation behavior of mixtures of tamarind seed xyloglucan (TSX) and sodium form gellan (Na-G) was investigated. The storage and loss shear moduli, G' and G'', of the mixtures showed that a thermoreversible gel was obtained although each polysaccharide alone did not form a gel at experimental conditions. The viscoelastic behavior of the mixtures showed a gel formation of TSX and Na-G induced by synergistic interaction. This synergistic interaction was also revealed by differential scanning calorimetry (DSC) and circular dichroism. Although TSX alone did not show any peak in DSC curves, mixtures with only a small amount of Na-G, which by itself did not show any peak, showed a single peak. With increasing Na-G content, another peak began to appear at the same temperature at which a peak of Na-G alone appeared. Thermally induced changes in circular dichroism of the mixtures were different from those expected from the individual behavior of TSX and Na-G.