Autocrine or paracrine inflammatory actions of corticotropin-releasing hormone in vivo

Corticotropin-releasing hormone (CRH) functions as a regulator of the hypothalamic-pituitary-adrenal axis and coordinator of the stress response. CRH receptors exist in peripheral sites of the immune system, and CRH promotes several immune functions in vitro. The effect of systemic immunoneutralization of CRH was tested in an experimental model of chemically induced aseptic inflammation in rats. Intraperitoneal administration of rabbit antiserum to CRH caused suppression of both inflammatory exudate volume and cell concentration by approximately 50 to 60 percent. CRH was detected in the inflamed area but not in the systemic circulation. Immunoreactive CRH is therefore produced in peripheral inflammatory sites where, in contrast to its systemic indirect immunosuppressive effects, it acts as an autocrine or paracrine inflammatory cytokine.     

Polymerization-induced epitaxy: scanning tunneling microscopy of a hydrogen-bonded sheet of polyamide on graphite

A molecularly thin film of a two-dimensional polymer network formed by hydrogen bonding was synthesized and investigated with scanning tunneling microscopy. Poly(in-caprolactam) (nylon 6) was epitaxially grown on the basal plane of graphite and an ultrathin film of the polymer was obtained after the bulk materials had been washed away with solvents. The polymer chain has a planar, all-trans conformation and adjacent chains run in the antiparallel direction. This produces complete pairing of hydrogen bonding groups, with each amide group lying on a straight line perpendicular to the polymer backbone. This hydrogen-bonded sheet is oriented so that each polymer backbone lies in the (1010) direction on the graphite hexagonal lattice, as opposed to the (1120) direction taken by other paraffinic molecules studied so far. This experiment shows that hydrogen bonding can be used to control the orientation of macromolecules in two dimensions.     

鹌鹑同工酶多型性的研究

采用水平板淀粉凝胶电泳法 ,对中国目前大规模饲养的 2个蛋用品系鹌鹑的脏器、肌肉中 1 0个酶基因座多型进行检测 ,结果表明 :朝鲜龙城系和德国红鸟系鹌鹑在 Adh、Es-D、Es、Pgi、6-Pgi、Mpi- 6个基因座位均发现多态 ,在Mdh- 、Mdh- 、Mpi- 、α-Gpd 4个基因座位均为单态。引用国外研究结果 ,对国内外 2 1个鹌鹑群体进行聚类分析 ,结果表明 :野生鹌鹑群紧密聚为一类 ,家养鹌鹑群聚为一类 ,商品用鹌鹑和实验用鹌鹑无明显分化 ,而大体重鹌鹑与一般体重鹌鹑分化较大 ,可能是由于进行体重选择的群体偶然携带了不同于原种群的特定基因     

Rates of chemical weathering of porous rhyolites: 5-year measurements using the weight-loss method

To examine the rate of chemical weathering, field experiments using microweight-loss techniques were carried out. Two kinds of porous rhyolite forming lava domes in Kozu-shima Island were selected: (1) a younger rock (weathering period is 2.6 ka) and (2) an older rock (20 ka). Both rocks seem to have been very similar in their initial composition and structure. They have, however, different properties in the present depending on the difference in weathering period. Rock tablets of these rhyolites with a diameter of 3.5 cm and a thickness of about 1 cm were enclosed in a nylon mesh bag and placed in a soil–bedrock interface on a hillslope of central Japan for over 5 years. The younger rock has a lower weight loss by about 0.5%, and the older rock has a higher weight loss of 3% to 5%. These results show that older rock has a higher rate of chemical weathering than in younger rock. This supports Oguchi et al.'s (Oguchi, T.C., Hatta, T., Matsukura, Y., 1994. Changes in rock properties of porous rhyolite through 40,000 years in Kozu-shima Island, Japan. Geogr. Rev. Jpn. 67A, 775–793 (in Japanese, with English Abstr.); Oguchi, T.C., Hatta, T., Matsukura, Y., 1999. Weathering rates over 40,000 years based on changes in rock properties of porous rhyolite. Phys. Chem. Earth (A) 24, 861–870.) finding that the rate of change in chemical properties appears to accelerate with weathering time.     

Antiallergic tea catechin, (-)-epigallocatechin-3-O-(3-O-methyl)-gallate,suppresses FcepsilonRI expression in human basophilic KU812 cells

We previously found that the O-methylated derivative of (-)-epigallocatechin-3-O-gallate (EGCg), (-)-epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG' '3Me), has potent antiallergic activity. The high-affinity IgE receptor, FcepsilonRI, is found at high levels on basophils and mast cells and plays a key role in a series of acute and chronic human allergic reactions. To understand the mechanism of action for the antiallergic EGCG' '3Me, the effect of EGCG' '3Me on the cell surface expression of FcepsilonRI in human basophilic KU812 cells was examined. Flow cytometric analysis showed that EGCG' '3Me was able to decrease the cell surface expression of FcepsilonRI. Moreover, immunoblot analysis revealed that total cellular expression of the FcepsilonRI alpha chain decreased upon treatment with EGCG' '3Me. FcepsilonRI is a tetrameric structure comprising one alpha chain, one beta chain, and two gamma chains. The level of mRNA production of each subunit in KU812 cells was investigated. EGCG' '3Me reduced FcepsilonRI alpha and gamma mRNA levels. The cross-linkage of FcepsilonRI causes the activation of basophils, which leads to the secretion of inflammatory mediators including histamine. EGCG' '3Me treatment inhibited the FcepsilonRI cross-linking-induced histamine release. These results suggested that EGCG' '3Me can negatively regulate basophil activation through the suppression of FcepsilonRI expression.     

Aggregates and gel network structure of globin hydrolysates

A gel with excellent functional properties was prepared successfully using the hydrolysates of globin. In the present study, the structures of intermediate aggregates and gel network were observed directly with an electronic microscope. It was shown clearly that the intermediate aggregates were in a thin rod shape with a length of 130--140 nm, which was in good accordance with the results of the light scattering obtained in a previous study. The diameter of intermediate aggregates was 4--5 nm. Each unit of the intermediate aggregate was composed of beta-chain and peptide beta-1 in a ratio of 1:1. Its molecular weight was 26922 Da, and it had a diameter of 4.1 nm. The thin rod-shaped aggregates were formed with units through the hydrophobic interaction. The length of intermediate aggregate was >30--33 times the diameter. Furthermore, the cross-linked structure formed by peptide alpha-1 and the thin rod-shaped aggregates was also confirmed by the photography of the electronic microscope. These results supported the model proposed in previous papers as proper to depict exactly the formation and structure of the gel network of globin hydrolysates.     

Interdigital involvement in a case of primary cutaneous canine histoplasmosis in Japan

A 5-year-old male Siberian husky bred outdoor in Tokyo had a swollen paw with interdigital granulomatous lesions in the left hindlimb. The dog had no apparent pulmonary or gastrointestinal involvement. Histopathological analysis of the skin lesions demonstrated yeast-like organisms predominantly within macrophages. Sequence analysis of fungal ribosome RNA gene isolated from a paraffin sample revealed a 100% homology with the teleomorph of Histoplasma capsulatum. The present case may support the concept of primary cutaneous canine histoplasmosis as an endemic phenotype recognized in Japan.     

Isolation of a human erythrocyte-adapted substrain of Babesia rodhaini and analysis of the merozoite surface protein gene sequences

Babesia rodhaini is a rodent hemoparasite closely related to B. microti, the major causative agent of human babesiosis. We tested the infectivity of B. rodhaini for human erythrocytes by using the SCID mouse model in which the circulating erythrocytes were replaced with those of humans. Initially, parasites grew very poorly in the mouse model, but a variant capable of propagating in human erythrocytes emerged after an adaptation period of three weeks. In an attempt to identify parasite proteins involved in the alteration of host cell preference, an expression cDNA library of B. rodhaini was constructed and screened with immune mouse sera. Although we were able to obtain three merozoite surface protein (MSP) genes, sequences of these genes from both the parental strain and human erythrocyte-adapted substrain were identical. Our results suggest that B. rodhaini has potential ability to infect human erythrocytes, but development of this ability may not be brought about by an amino acid change in MSPs.