Ecological studies of aquatic moss pillars in Antarctic lakes 2. Temperature and light environment at the moss habitat

To understand the environmental conditions, which control the growth of moss pillars in lake bottoms, water temperature and light in the moss pillar habitat in lake Kuwai Ike in Skarvsnes, Soya Coast, East Antarctica, were continuously measured for about one year, February 1999 to Jannuary 2000. Limnological characteristics of surface water of the lake were investigated in summer 2000, and compared with those in four neighboring lakes. Low contents of ions, neutral pH and dissolved oxygen in saturation level in the surface water in Kuwai-Ike lake were comparable to the values of the other oligotrophic freshwater lakes in Soya Coast and Schirmacher Oasis, located in Queen Maud Land, East Antarctica. The temperature at the lake bottom showed uni-modal seasonal change, in the range 0-12°C. Several sudden temperature drops of > 2°C within a few hours were recorded in the ice-free autumn season; they may have been correlated with the wind-induced vertical mixing events which occurred before complete ice cover development on the lake surface. Light reaching the lake bottom showed clear diel and seasonal fluctuations, and the flux density was strongly affected by the attenuations of water, ice and snow: the photosynthetically active radiation (PAR) measured at the lake bottom was s^ was recorded for nearly 2 months in winter; however, daily fluxes over 1 mol m^ day^ were recorded for the other ca. 8 months, with >100μmol m^ s^ of instantaneous peak fluxes around noon

Acclimation of photosynthetic properties in psychrophilic diatom isolates under different light intensities

Acclimation of growth and photosynthetic properties was examined for diatom strains, isolated from Saroma Ko lagoon (44°N, 144°E) in early spring, under different light intensities at 1℃. The relatively high specific growth constants under low irradiances were recognized for both Chaetoceros sp. and Thalassiosira sp. Further examination of photosynthesis in Chaetoceros sp. showed that growth under low irradiance caused an increase in the photosynthetic effciency for Chl α-specific rate of gross O_2 evolution (α^B) and a decrease in the Chl α-specific rate of dark O_2 respiration (R_d^B), which was extrapolated from the initial slope of net O_2 evolution rate vs. irradiance curve. These changes explain the low light compensation point for net photosynthetic O_2 evolution (I_c) and the high efficiency for growth under low irradiance conditions. Neither Chl α-specific amounts of light-harvesting pigments, such as fucoxanthin and Chl c, nor cellular content of Chl α, but Chl α-specific amount of diadinoxanthin was varied by the change in irradiance condition. The increase of α^B under low growth irradiance corresponded with a decrease in the amount of diadinoxanthin relative to Chl α. However, the Chl α-specific maximum photosynthetic rate (P_m^B) was retained at the same level and photoinhibition could not be observed under illumination up to &acd;800μE m^ s^. The light intensity at which photosynthesis was light-saturated (I_k, =P_m^B/α^B) was much higher than the incident growth irradiances (76 and 88μE m^ s^ under the growth irradiances of 11 and 42 μE m^ s^, respectively), although the value of I_k for the former was significantly smaller (t-test, P<0.001) than that for the latter. Thus, the capacity of photochemical reaction around photosystems seems to remain large even under low irradiance. These properties may indicate that the diatom cells could efficiently utilize light-energy under large variation of irradiance even on a short time-scale

Antibacterial Effects of Disulfiram in Helicobacter pylori

Background: Helicobacter pylori infection poses a risk of the occurrence of gastrointestinal diseases, such as gastric cancer. Its incidence rate is significantly reduced by eradication, and thereby, eradication therapy is generally performed. Disulfiram is an oral prescription drug mainly used for the treatment of alcohol dependence. In recent years, reports have been made on its anticancer and antibacterial effects, and thus, it has recently become an interesting subject. This study aimed to examine the antibacterial activity of disulfiram, investigate the presence or absence of its antibacterial activity on H. pylori, and determine whether it could be a new bactericidal drug against drug-resistant H. pylori. Materials and Methods: Drug-sensitive strains of H. pylori and amoxicillin-resistant, clarithromycin-resistant, and metronidazole-resistant strains were used, and a growth inhibition test of H. pylori using disulfiram was performed. Furthermore, the expression of urease, vacuolating cytotoxin A (VacA), and CagA, the virulence proteins of H. pylori, was quantitatively analyzed using the Western blotting method. In addition, for H. pylori used in this study, the 16SrDNA sequence, a ribosomal gene involved in protein production, was analyzed to examine the presence or absence of gene mutation. Results: Disulfiram suppressed the growth of 7 out of 12 H. pylori strains at 1 mu g/mL, and no correlation was observed between their susceptibility/resistance to current eradication antimicrobial drugs and disulfiram resistance. Disulfiram reduced the expression levels of urease, VacA, and CagA proteins. H. pylori, which showed resistance to disulfiram, tended to have fewer gene deletions/insertions in the 16S rDNA sequence; however, no specific mutation was detected. Conclusion: Disulfiram has a bactericidal effect on H. pylori at low concentrations, suggesting that it can be used as a supplement for current H. pylori eradication drugs

Development of hydroxyapatite-coated nonwovens for efficient isolation of somatic stem cells from adipose tissues

Adipose-derived stem cells (ASCs) are an attractive cell source for cell therapy. Despite the increasing number of clinical applications, the methodology for ASC isolation is not optimized for every individual. In this study, we developed an effective material to stabilize explant cultures from small-fragment adipose tissues. Methods: Polypropylene/polyethylene nonwoven sheets were coated with hydroxyapatite (HA) particles. Adipose fragments were then placed on these sheets, and their ability to trap tissue was monitored during explant culture. The yield and properties of the cells were compared to those of cells isolated by conventional collagenase digestion. Results: Hydroxyapatite-coated nonwovens immediately trapped adipose fragments when placed on the sheets. The adhesion was stable even in culture media, leading to cell migration and proliferation from the tissue along with the nonwoven fibers. A higher fiber density further enhanced cell growth. Although cells on nonwoven explants could not be fully collected with cell dissociation enzymes, the cell yield was significantly higher than that of conventional monolayer culture without impacting stem cell properties. Conclusions: Hydroxyapatite-coated nonwovens are useful for the effective primary explant culture of connective tissues without enzymatic cell dissociation

Site-specific differences in T lymphocyte composition of the gastric mucosa after Helicobacter pylori eradication

In our earlier work, we revealed that inflammation of the lesser curvature of the gastric body and antrum could constitute independent risk factors for gastric cancer development, while inflammation of the greater curvature was not. The aims of this study were as follows: first, to reveal the differences between T lymphocyte populations of the gastric antrum and the greater and lesser curvatures of the gastric body in patients after Helicobacter pylori eradication; second, to analyze the correlation between the composition of the stomach-resident T lymphocytes and time from H. pylori eradication; and third, to evaluate the sex differences in T lymphocyte subsets after H. pylori eradication. To investigate site-specific differences in stomach-resident T lymphocytes after H. pylori eradication, we performed flow cytometry analysis on samples taken from the gastric antrum, greater curvature of the gastric body, and lesser curvature of the gastric body of 20 patients. We also analyzed the correlation between the composition of the stomach-resident T lymphocytes and the time from H. pylori eradication. The lymphocyte subsets of the antrum and lesser curvature of the body were similar. In contrast, compared to those in the greater curvature of the gastric body, CD4(+)/CD3(+) lymphocyte subsets (43.8 +/- 19.4% vs 31.7 +/- 14.6%) were elevated in the lesser curvature of the body, whereas CD8(+)/CD3(+) (67.1 +/- 21.3% vs 80.4 +/- 12.0%), CD7(+)/CD3(+) (91.2 +/- 4.6% vs 93.7 +/- 3.8%), CCR4(+)/CD3(+) (7.7 +/- 8.1% vs 10.4 +/- 7.0%), CD45RA(+)/CD3(+)CD4(+) (27.2 +/- 24.8% vs 39.5 +/- 20.8%), and CD45RA(+)/CD3(+)CD4(-) (14.2 +/- 11.1% vs 18.7 +/- 11.5) were lower. Linear regression analysis showed a negative correlation between the time after H. pylori eradication and CD4(+)/CD3(+) (P < .05, R-2 = 0.198). There were no significant differences between men and women with respect to the lymphocyte populations. These results indicate that there are site-specific differences in lymphocyte composition in the stomach after H. pylori eradication

Exploratory classification of clinical phenotypes in Japanese patients with antineutrophil cytoplasmic antibody-associated vasculitis using cluster analysis

A novel patient cluster in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) may be identified in Japan. We performed multiple correspondence and cluster analysis regarding 427 clinically diagnosed AAV patients excluding eosinophilic granulomatosis with polyangiitis. Model 1 included the ANCA phenotype, items of the Birmingham Vasculitis Activity Score, and interstitial lung disease; model 2 included serum creatinine (s-Cr) and C-reactive protein (CRP) levels with model 1 components. In seven clusters determined in model 1, the ANCA-negative (n=8) and proteinase 3-ANCA-positive (n=41) groups emerged as two distinct clusters. The other five myeloperoxidase-ANCA-positive clusters were characterized by ear, nose, and throat (ENT) (n=47); cutaneous (n=36); renal (n=256), non-renal (n=33); and both ENT and cutaneous symptoms (n=6). Four clusters in model 2 were characterized by myeloperoxidase-ANCA negativity (n=42), without s-Cr elevation (1.3 mg/dL) with high CRP (>10 mg/dL) (n=71), or s-Cr elevation (>= 1.3 mg/dL) without high CRP (<= 10 mg/dL) (n=157). Overall, renal, and relapse-free survival rates were significantly different across the four clusters in model 2. ENT, cutaneous, and renal symptoms may be useful in characterization of Japanese AAV patients with myeloperoxidase-ANCA. The combination of s-Cr and CRP levels may be predictive of prognosis