Effects of the Sri Lankan medicinal plant, Salacia reticulata, in rheumatoid arthritis

Salacia reticulata is a native plant of Sri Lanka. In the traditional medicine of Sri Lanka and India, Salacia reticulata bark is considered orally effective in the treatment of rheumatism, gonorrhea, skin disease and diabetes. We have investigated, both in vivo and in vitro, whether the leaf of Salacia reticulata (SRL) can ameliorate collagen antibody-induced arthritis (CAIA) in mice as the rheumatoid arthritis (RA) model. The mice were fed a lard containing chow diet (AIN-93G) or the same diet containing 1% (w/w) SRL powder. All mice were bred for 23 days. On day 7 or 14 after LPS injection, mice were killed, and tissue and blood samples were collected. Histological analysis was performed, and serum levels of inflammatory mediators and the mRNA levels of inflammation-related genes and osteoclast-related genes were measured. SRL treatment ameliorated the rapid initial paw swelling, inflammatory cells infiltration, skeletal tissues damage, osteoclast activation and the mRNA levels for osteoclast-related genes compared with the CAIA mice. However, the serum and mRNA levels of inflammatory mediators did not differ between the CAIA mice and the SRL-treated mice. SRL might reduce the inflammatory cells induction and skeletal tissue degradation by CAIA by the regulating osteoclastogenesis.     

Identification of QTLs controlling somatic embryogenesis using RI population of cultivar × weedy soybean

Quantitative trait loci (QTLs) controlling ability of somatic embryogenesis were identified in soybean. A frame map with 204-point markers was developed using an RI population consisting of 117 F₁₁ lines derived from a cross between cultivar ‘Keburi’ and a weedy soybean ‘Masshokutou Kou 502’. The parents differed greatly in their abilities of somatic embryogenesis using immature cotyledons as explants. The ability of somatic embryogenesis was evaluated in five different experiments: the F₁₁ (evaluated in 1998) and F₁₅ (2002) generations cultured on basal media supplemented with 40 mg l⁻¹ 2,4-D (2,4-D1998 and 2,4-D2002), F₁₄ (2001) generation on medium with 40 mg l⁻¹ 2,4-D and high sucrose concentration [2,4-D2001 (30 g l⁻¹ sucrose)], and the F₁₁ (1998) and F₁₂ (1999) generations on medium with 10 mg l⁻¹ NAA (NAA1998 and NAA1999). The RILs showed wide and continuous variations in each of the five experiments. In the composite interval mapping analysis, 2 QTLs were found in group 8 (D1b + W, LOD = 5.42, r ² = 37.5) in the experiment of 2,4-D1998 and in group 6 (C2, LOD = 6.03, r ² = 26.0) in the experiment of 2,4-D2001 (high concentration sucrose). In both QTLs, alleles of ‘Masshokutou Kou 502’ with high ability of somatic embryogenesis contributed to the QTLs. For the other three experiments, no QTL was detected in the criteria of LOD >3.0, suggesting the presence of minor genes.     

Light regulates alternative splicing of hydroxypyruvate reductase in pumpkin

Hydroxypyruvate reductase (HPR) is a leaf peroxisomal enzyme that functions in the glycolate pathway of photorespiration in plants. We have obtained two highly similar cDNAs for pumpkin HPR (HPR1 and HPR2). It has been revealed that two HPR mRNAs might be produced by alternative splicing from a single type of pre-mRNA. The HPR1 protein, but not the HPR2 protein, was found to have a targeting sequence into leaf peroxisomes at the C-terminus, suggesting that alternative splicing controls the subcellular localization of the two HPR proteins. Immunoblot analysis and subcellular fractionation experiments showed that HPR1 and HPR2 proteins are localized in leaf peroxisomes and the cytosol, respectively. Moreover, indirect fluorescence microscopy and analyses of transgenic tobacco cultured cells and Arabidopsis thaliana expressing fusion proteins with green fluorescent protein (GFP) revealed the different subcellular localizations of the two HPR proteins. Both mRNAs were induced developmentally and by light, but with quantitative differences. Almost equal amounts of the mRNAs were detected in pumpkin cotyledons grown in darkness, but treatment with light greatly enhanced the production of HPR2 mRNA. These findings indicate that light regulates alternative splicing of HPR mRNA, suggesting the presence of a novel mechanism of mRNA maturation, namely light-regulated alternative splicing, in higher plants.     

Pathophysiology of orthostatic hypotension after bed rest: paradoxical sympathetic withdrawal

Although orthostatic hypotension is a common clinical syndrome after spaceflight and its ground-based simulation model, 6 degrees head-down bed rest (HDBR), the pathophysiology remains unclear. The authors' hypothesis that a decrease in sympathetic nerve activity is the major pathophysiology underlying orthostatic hypotension after HDBR was tested in a study involving 14-day HDBR in 22 healthy subjects who showed no orthostatic hypotension during 15-min 60 degrees head-up tilt test (HUT) at baseline. After HDBR, 10 of 22 subjects demonstrated orthostatic hypotension during 60 degrees HUT. In subjects with orthostatic hypotension, total activity of muscle sympathetic nerve activity (MSNA) increased less during the first minute of 60 degrees HUT after HDBR (314% of resting supine activity) than before HDBR (523% of resting supine activity, P < 0.05) despite HDBR-induced reduction in plasma volume (13% of plasma volume before HDBR). The postural increase in total MSNA continued during several more minutes of 60 degrees HUT while arterial pressure was maintained. Thereafter, however, total MSNA was paradoxically suppressed by 104% of the resting supine level at the last minute of HUT (P < 0.05 vs. earlier 60 degrees HUT periods). The suppression of total MSNA was accompanied by a 22 +/- 4-mmHg decrease in mean blood pressure (systolic blood pressure <80 mmHg). In contrast, orthostatic activation of total MSNA was preserved throughout 60 degrees HUT in subjects who did not develop orthostatic hypotension. These data support the hypothesis that a decrease in sympathetic nerve activity is the major pathophysiological factor underlying orthostatic hypotension after HDBR. It appears that the diminished sympathetic activity, in combination with other factors associated with HDBR (e.g., hypovolemia), may predispose some individuals to postural hypotension.     

Low concentrations of propyzamide and oryzalin alter microtubule dynamics in Arabidopsis epidermal cells

Previous studies showed that sub-micromolar concentrations of the microtubule-targeting herbicide propyzamide cause a right-handed helical arrangement of cortical microtubule arrays and left-handed twisting in elongating Arabidopsis epidermal cells. When seedlings were grown in the presence of 1-2 microM propyzamide or 50-100 nM oryzalin, we show that microtubules spent more time in a paused state in which they exhibited little net change in length. The drug treatment also resulted in slower growth and shortening velocities, increased catastrophe, and an overall decrease in microtubule turnover. A reduction in microtubule dynamic turnover may underlie the drug-induced rearrangement of cortical arrays.     

Novel imidazole compounds as a new series of potent,orally active inhibitors of 5-lipoxygenase

Replacement of the dihydroquinolinone pharmacophore of Zeneca's ZD2138 by ionizable imidazolylphenyl moiety has lead to the discovery of a novel series of potent and orally active 5-lipoxygenase (5-LO) inhibitors. The synthesis and structure-activity relationship (SAR) of this series of compounds are described herein.     

Intraspecific variability of the tandem repeats in Nicotiana putrescine N-methyltransferases

Plant Molecular Biology -     

CONTRIBUTION OF CIRCULATING LEUKOCYTES TO CYTOKINE PRODUCTION IN PANCREATIC DUCT OBSTRUCTION-INDUCED ACUTE PANCREATITIS IN RATS

Little information is available regarding the role of circulating leukocytes in the pathogenesis of acute pancreatitis (AP). Our aim was to explore the time-course of the potential role of inflammatory peripheral blood (PB) cells during AP induced in rats by pancreatic duct obstruction (PDO). Flow cytometry immunophenotyping was used to analyse the distribution of the major circulating leukocyte subsets, the activation state of circulating monocytes as reflected by both CD11b expression and TNF-α production and the relative contribution of T-cell derived pro- (TNF-α) and anti- (IL-10) inflammatory mediators at different stages of PDO-induced AP. A progressive increase in PB neutrophils and monocytes was observed up to 6 h after PDO whereas lymphocytes, as well as CD4⁺ and CD8⁺ T-cell subsets, rose as early as 1.5 h after PDO and decreased thereafter. Monocytes were activated in PB from 6 h after inducing AP as reflected by increases in both CD11b expression and spontaneous TNF-α production; nevertheless, they showed the capability of producing TNF-α at earlier AP stages by lipopolysaccharide (LPS) stimulation. In contrast, T-cells were unable to produce TNF-α during AP neither spontaneously nor after stimulation with PMA/Ionomycin. Therefore, only PB monocytes contribute to increase TNF-α levels in plasma as observed from 12 h onwards after inducing AP. Interleukin-10 was produced by T-cells 6 h after PDO only after PMA/Ionomycin stimulation. We conclude that systemic inflammatory events are triggered off at early stages of PDO-induced AP, with the activation of circulating monocytes, though not T-cells, playing a central role.     

Tumoricidal effect of human macrophage-colony-stimulating factor against human-ovarian-carcinoma-bearing athymic mice and its therapeutic effect when combined with cisplatin

The effect of human macrophage-colony-stimulating factor (hM-CSF) on tumoricidal activity was examined in athymic mice bearing the human ovarian cancer cell line, HRA, injected intraperitoneally (i.p.). The survival period and survival rate in the groups treated daily with hM-CSF were significantly longer (P<0.01) than in the untreated group. The peritoneal cell smears showed that ascitic tumor cells were markedly decreased in the hM-CSF-treated groups, and macrophages phagocytosed tumor cells, indicating a contact-mediated direct cytolysis. The combined therapeutic effects of cisplatin and hM-CSF on HRA-bearing athymic mice were also studied. The mean survival period was 25.4, 47.2, 42.4 and 67.4 days, respectively, in the untreated group, and in the groups treated with cisplatin alone, with hM-CSF alone, and with combined cisplatin and hM-CSF. The survival period and rate were significantly longer (P<0.01) in the group treated with combined cisplatin and hM-CSF than in those treated with cisplatin or hM-CSF alone, indicating the therapeutic effectiveness of the combined use. Morever, hM-CSF is effective against granulocytopenia due to bone marrow suppression caused by cisplatin. Our data demonstrate that hM-CSF administered i.p. has a tumoricidal activity in athymic mice bearing human ovarian cancer i.p., which is mediated by activated macrophages, and that the combined administration of cisplatin and hM-CSF has a significant therapeutic effect.     

Mutagenicity of blue rayon extracts of human bile in the Ames test

The mutagenicity of human bile was examined in the Ames Salmonella/microsome assay. Bile samples were obtained from the gallbladders resected from patients with cholelithiasis, choledocholithiasis, gallbladder cancer, extrahepatic bile duct cancer and other disease. For extraction of mutagenic components, the bile samples were treated with blue rayon and the adsorbed materials were assayed with Salmonella typhimurium TA98 in the presence of S9 mix. Twenty-four bile samples were tested and positive mutagenic activity was found in 14 samples. A 200-μl bile equivalent material gave 6.3 times as many revertant colonies as the solvent control. With several samples that had undergone two cycles of blue rayon extraction, clear dose-response relationships in mutagenicity were demonstrated.