Mechanism of Action of Bacillus thuringiensis Insecticidal Delta-endotoxin on Insect Cells in Vitro

Cultured insect cells, TN-368 from the cabbage looper, swelled and burst upon treatment with the enzyme-digested delta-endotoxin of Bacillus thuringiensis var. aizawai. The cytotoxic sweelling was depended upon the amount of the delta-endotoxin added and the concentration of NaCl or KC1 in the isotonic solution. The concentration of Na⁺ in the swollen cells approximately doubled in isotonic NaCl, while that of K⁺ decreased to 10% of the original cellular concentration. The cell swelling was inhibited by tetrodotoxin and also by ouabain in only KC1 isotonic solution. On the other hand, 4-aminopyridine stimulated the swelling in the isotonic KC1 solution, These results indicate that the delta-endotoxin induces the stimulation of Na+ influx and K+ efflux in the isotonic NaCl solution, and also stimulates the Na⁺, K⁺-ATPase in the isotonic KC1 solution. The cytotoxic swelling was also blocked by cAMP, AMP, ATP, GTP, and NAD, but not by adenosine and GMP. These results suggest the participation of nucleotide derivatives in the action of delta-endotoxin.     

Enzymatic fragmentation of carbohydrate moieties of radish arabinogalactan-protein and elucidation of the structures

We investigated the structures of L-arabino-galactooligosaccharides released from the sugar moieties of a radish arabinogalactan-protein (AGP) by the action of exo-β-(1→3)-galactanase. We detected a series of neutral β-(1→6)-linked galactooligosaccharides forming branches of one to up to at least 19 consecutive Gal groups, together with corresponding acidic derivatives terminating in 4-O-methyl-glucuronic acid (4-Me-GlcA) at the non-reducing end. Some oligosaccharide chains of degree of polymerization (dp) higher than 3 for neutral, and 4 for acidic oligomers were modified with L-Araf residues. The acidic tetrasaccharide 4-Me-β-GlcA-(1→6)[α-L-Araf-(1→3)]-β-Gal-(1→6)-Gal was detected as an abundant L-Araf-containing oligosaccharide among these neutral and acidic oligomers. A pentasaccharide containing an additional L-Araf group attached to the L-Ara in the tetrasaccharide through an α-(1→5)-linkage was also found. We observed L-arabino-galactooligosaccharides substituted with single or disaccharide L-Araf units at different Gal residues along these neutral and acidic β-(1→6)-galactooligosaccharide chains, indicating that these side chains are highly variable in length and substituted variously with L-Araf residues.     

Analysis of Factors That Determine Weight Gain during Smoking Cessation Therapy

Cigarette smokers are generally known to gain weight after quitting smoking, and such weight gain is thought to contribute to the worsening of glucose tolerance. While smoking cessation therapy such as nicotine replacement is useful to minimize post-cessation weight gain, substantial gain occurs even during the therapy. The purpose of the present study was to identify factors associated with weight gain during smoking cessation therapy. We evaluated 186 patients(132 males and 54 females)who visited our outpatient clinic for smoking cessation, and successfully achieved smoking abstinence. We performed gender-adjusted regression analysis for the rate of BMI increase from the beginning of cessation to 3 months after initiation. Furthermore, we performed multivariate analysis to investigate factors that determine the BMI increase after smoking cessation. The mean BMI significantly (p<0.0001) increased from 23.5±3.6 kg/m² at the initial consultation to 23.9±3.8 kg/m² at 3 months after the start of therapy. There was no significant difference in the extent of BMI increase between nicotine patch and varenicline therapy groups. Factors significantly correlated with the %BMI increase at 3 months after the start of therapy were triglyceride (p = 0.0006, βa = 0.260), high-density lipoprotein cholesterol (p = 0.0386, βa = −0.168), daily cigarette consumption (p = 0.0385, βa = 0.154), and the Fagerström Test for Nicotine Dependence (FTND) score (p = 0.0060, βa = 0.203). Stepwise multivariate analysis demonstrated that triglyceride and the FTND score were the factors determining the post-cessation BMI increase and that the FTND score was the strongest one. The present study demonstrated that smokers with a high FTND score are more likely to gain weight during smoking cessation therapy. Thus, smokers with a high nicotine dependency may require intervention against weight gain in the cessation clinic.     

Carbenoxolone Disodium Treatment for Canine Pituitary-Dependent Hyperadrenocorticism

Pituitary-dependent hyperadrenocorticism (PDH) is mainly caused by pituitary corticotroph tumors in dogs. A characteristic feature of corticotroph tumors is their resistance to negative feedback by glucocorticoids. In some animal species, including dogs, the aberrant expression of 11β-hydroxysteroid dehydrogenase (11HSD), a cortisol metabolic enzyme, is observed in corticotroph tumors. We previously reported that carbenoxolone (CBX), an inhibitor of 11HSD, suppressed ACTH secretion from the pituitary gland, and decreased cortisol concentrations in healthy dogs. Therefore, the aim of this study was to investigate the therapeutic effects of CBX on dogs with PDH. Six dogs with PDH were treated with 60 to 80 mg/kg/day of CBX for 6 weeks, followed by trilostane, which is a commonly used agent for canine PDH. CBX treatment led to a gradual decrease in both basal and in corticotropic releasing hormone (CRH)-stimulated plasma ACTH concentrations and CRH-stimulated serum cortisol concentrations, without side effects. However, basal and stimulated ACTH and cortisol concentrations remained higher than those of healthy dogs, and clinical symptoms such as polydipsia and polyuria were not ameliorated. After a 2-week wash-out interval, trilostane was administered for 2 weeks. Although basal plasma ACTH concentrations were higher after trilostane treatment than CBX treatment, polydipsia and polyuria resolved in all six dogs. The reason for the lack of improvement in polydipsia and polyuria with CBX treatment is unclear. Other mechanisms, in addition to a partial decrease in ACTH secretion, are likely to be involved. In conclusion, this is the first study to report the in vivo effects of CBX in dogs with PDH. The findings suggest that CBX inhibits ACTH secretion from canine pituitary tumors, resulting in lower cortisol concentrations.     

Activity of the neurons in the perifornical hypothalamic area during sleep and waking in comparison with those in the brainstem noradrenergic or cholinergic neurons

Sleep and Biological Rhythms -     

Quantitative and antioxidative behavior of Trolox in rats’ blood and brain by HPLC‐UV and SMFIA‐CL methods

Trolox, a water‐soluble vitamin E analogue has been used as a positive control in Trolox equivalent antioxidant capacity and oxygen radical antioxidant capacity assays due to its high antioxidative effect. In this study, the ex vivo antioxidative effects of Trolox and its concentration in blood and brain microdialysates from rat after administration were evaluated by newly established semi‐microflow injection analysis, chemiluminescence detection and HPLC‐UV. In the administration test, the antioxidative effect of Trolox in blood and brain microdialysates after a single administration of 200 mg/kg of Trolox to rats could be monitored. The antioxidative effects in blood (12.0 ± 2.1) and brain (8.4 ± 2.1, × 10³ antioxidative effect % × min) also increased. Additionally, the areas under the curve (AUC)s_0–360 (n = 3) for blood and brain calculated with quantitative data were 10.5 ± 1.2 and 9.7 ± 2.5 mg/mL × min, respectively. This result indicates that Trolox transferability through the blood–brain barrier is high. The increase in the antioxidative effects caused by Trolox in the blood and brain could be confirmed because good correlations between concentration and antioxidative effects (r ≥ 0.702) were obtained. The fact that Trolox can produce an antioxidative effect in rat brain was clarified. Copyright © 2015 John Wiley & Sons, Ltd.     

Septicemia from Lactobacillus rhamnosus GG,from a Probiotic Enriched Yogurt,in a Patient with Autologous Stem Cell Transplantation

Probiotics and Antimicrobial Proteins - Probiotic-rich foods are consumed without much restriction. We report here, a case of septic shock caused by yogurt derived Lactobacillus species in a...     

Intercellular signaling between ameloblastoma and osteoblasts

Ameloblastoma is an odontogenic tumor located in the bone jaw with clinical characteristics of extensive bone resorption. It is a locally invasive tumor with a high recurrence rate despite adequate surgical removal. In bone disease, tumors and other cells including osteoblasts, osteoclasts, and osteocytes in the bone microenvironment contribute to the pathogenesis of tumor growth. However, the effect of osteoblasts on ameloblastoma cells is not well-understood, and there has been limited research on interactions between them.This study investigated interactions between ameloblastoma cells and osteoblasts using a human ameloblastoma cell line (AM-3 ameloblastoma cells) and a murine pre-osteoblast cell line (MC3T3-E1 cells). We treated each cell type with the conditioned medium by the other cell type. We analyzed the effect on cytokine production by MC3T3-E1 cells and the production of MMPs by AM-3 cells. Treatment with AM-3-conditioned medium induced inflammatory cytokine production of IL-6, MCP-1, and RANTES from MC3T3-E1 cells. The use of an IL-1 receptor antagonist suppressed the production of these inflammatory cytokines by MC3T3-E1 cells stimulated with AM-3-conditioned medium. The MC3T3-E1-conditioned medium triggered the expression of MMP-2 from AM-3 cells. Furthermore, we have shown that the proliferation and migration activity of AM-3 cells were accelerated by MC3T3-E1 conditioned media.In conclusion, these intercellular signalings between ameloblastoma cells and osteoblasts may play multiple roles in the pathogenesis of ameloblastoma.