bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interactions between bacteria and harmful algae: A review
Authors: Doucette Gregory J. 
Published: October 2006

AbstractThe ways in which bacteria interact with eukaryotic, unicellular algae are extremely diverse. Such relationships vary widely according to a number of criteria, including spatial and temporal scales, the degree of specificity, and if the relationship can be characterized as beneficial or detrimental to any of the organisms involved. These criteria can be applied to our assessment of how microbes interact with those species involved in the formation of harmful algal blooms (HABs). The aim of this paper is to assess the current state of our knowledge of bacterial/HAB interactions as they pertain to the influence of bacteria on HAB population dynamics, the role of bacteria in the production of toxins normally attributed to the algae, and the suggestion that HABs may act as vectors for pathogenic bacteria. Given that viruses are now considered to play a potentially important role in structuring phytoplankton communities, the possible effects of viruses on the population dynamics of harmful algal species are also addressed. © 1995 Wiley‐Liss, Inc.
Ethanolic extraction, purification, and partial characterization of a fluorescent toxin from the coral reef crab, Lophozozymus pictor
Authors: Lau C. O. , Tan C. H. , Khoo H. E. , Li Q. T. , Yuen R. 
Published: October 2006

AbstractA purification procedure for Lophozozymus pictor toxin (LPTX) following ethanolic extraction of whole crab homogenate is described. The ethanol‐extracted toxin (LPTX‐E) had higher yield and specific activity than the hot aqueous‐extracted one (LPTX‐H). It was found that LPTX‐E was fluorescent and cochromatographed with LPTX‐H on two‐dimensional thin‐layer chromatography. Although LPTX‐E, LPTX‐H, and palytoxin (P. caribaeorum, PTX) had similar migration and retention times when analysed on high performance capillary electrophoresis and gel permeation‐high performance liquid chromatography respectively, LPTX‐E and LPTX‐H were both fluorescent in contrast to PTX In addition, LPTX‐E had a different retention time compared with PTX when chromatographed on reversed phase high performance liquid chromatography in the solvent system 80% acetonitrile and 0.02 M Tris‐HCI, pH 7.2, at a 4:1 ratio, respectively, indicating some differences in their chemical structures. © 1995 Wiley‐Liss, Inc.
Fate in humans of dietary intake of cyanogenic glycosides from roots of sweet cassava consumed in Cuba
Authors: Hernández Teresa , Lundquist Per , Oliveira Lourdes , Cristià Rafael Perez , Rodriguez Elena , Rosling Hans 
Published: October 2006

AbstractWe studied if consumption of boiled fresh roots from sweet cassava varieties grown in Cuba resulted in exposure to cyanogenic glycosides and their final breakdown product, cyanide. When adult, nonsmoking subjects consumed 1‐4 kg cassava over 2 days, their urinary levels of the main cyanide metabolite, thiocyanate, only increased from a mean ± SEM of 12 ± 2 to 22 ± 2 μ.mol/l, indicating a negligible cyanide exposure. Their mean urinary linamarin, the main cyanogenic glucoside in cassava, increased from 2 ± 1 to 68 ± 16 μmol/l. In a second experiment 5 subjects consumed one meal of 0.5 kg boiled cassava that contained 105 μ‐mol linamarin and 8 μ.mol hydrogen cyanide (HCN). Quantitative urine collections prior to and after intake showed that 28% of linamarin was excreted during the following 24 hours, whereas a modest increase of urinary thiocyanate (SCN) only corresponded to the small amount of free HCN ingested. These results indicate that the dominant cyanogen in boiled cassava is glycosides that pass through the human body without causing cyanide exposure. It remains to be studied whether humans occasionally possess intestinal or tissue β‐glucosidases that can hydrolyse cyanogenic glycosides from cassava. © 1995 Wiley‐Liss, Inc.
Metabolism of the Fusarium mycotoxins zearalenone and deoxynivalenol by yeast strains of technological relevance
Authors: Böswald Christoph , Engelhardt Gabriele , Vogel Herbert , Wallnöfer Peter R. 
Published: October 2006

AbstractThe Fusarium mycotoxin zearalenone (ZEA), added at a level of 2 μ/ml, was reduced stereoselectively by cultures of Candida tropicalis, Torulaspora delbrückii, Zygosaccharomyces rouxii, and 7 Saccharomyces strains to both α‐ and β‐zearalenol. In contrast, only a‐zearalenol was produced from ZEA by Pichia fermentans and several yeast strains of the genera Candida, Hansenula, Brettanomyces, Schizosaccharomyces, and Saccharomycopsis. No glucose conjugates of ZEA (zearalenone‐4‐β‐D‐glucopyranoside) were detected. The trichothecene mycotoxin deoxynivalenol (DON) was not metabolized by any of the yeast strains that were used for analysis. © 1995 Wiley‐Liss, Inc.
Maitotoxin increases voltage independent chloride and sodium currents in GH4C1 rat pituitary cells
Authors: Young Roger C. , McLaren Matthew , Ramsdell John S. 
Published: October 2006

AbstractMaitotoxin (MTX) is a 3,424 dalton polyether marine toxin that causes influx of calcium through type L voltage‐dependent calcium channels (L‐VDCC) in GH4C1 rat pituitary cells, presumably as the result of membrane depolarization. In this study we have investigated the ionic conductances responsible for MTX‐induced depolarization under voltage clamp conditions using the perforated and ruptured patch methods. MTX‐induced steady‐state voltage independent currents of nearly 400 pS/pF within seconds of addition to the bath. Ion substitution experiments demonstrated these currents are consistent with the conductance of sodium and chloride, but not calcium, ions. MTX induction of the voltage‐independent chloride conductance in GH4C1 cells occurred concurrently without modification of L‐VDCC currents. Pretreatment with nimodipine eliminated voltage activation of L‐VDCC, and reduced by two thirds the voltage independent current. Analysis as a function of time of MTX exposure revealed that the first 60 sec of MTX‐induced currents were not affected by nimodipine pretreatment, but subsequent additional currents were prevented. This indicates that the initial currents induced by MTX occur independently of L‐VDCC mediated calcium entry, but full activation of these currents by MTX likely requires the involvement L‐VDCC. Taken together this work identifies a voltage‐independent sodium/chloride conductance as an initial action of MTX, one that may promote the sequence of ionic events leading to activation of L‐VDCC and massive calcium entry. © 1995 Wiley‐Liss, Inc.
The impact of clustering in physician and pharmacy services on the accuracy of pharmaceutical exposure risk estimates
Authors: Burkhart Greg A. , Hammerstrom Thomas 
Published: October 2006

AbstractRecord‐linkage databases have been used to evaluate the safety of approved drugs. Outcome and exposure data collected in these databases are contingent upon temporal contacts between patients and their physicians and pharmacists. We examined the theoretical effect of temporal clustering in physician and pharmacy services on pharmaceutical risk estimates by generating computer modeled datasets of the dates of provider services. Incidence density ratios were estimated for each dataset by comparing the incidence of the hypothetical outcome during exposure to that during no exposure. The presence of clustering in provider services, the risk associated with exposure, the length of the risk period, the number of refills and the underlying physician visit rates were varied by dataset. Biased estimates of the incidence density ratio were obtained in datasets with clustering. The magnitude of bias decreased with increasing length of the risk period, increasing number of refills and increasing physician visit rate. A sample of an HMO record‐linkage database showed evidence of clustering in physician visits at the patient level when the transaction dates for all physician visits were tested for clustering. Researchers using record‐linkage databases or data derived from patient interactions with providers to study the acute risk of pharmaceutical exposures, should consider the possibility of biased risk estimates for outcomes that cluster with other outcomes and exposure.
Drug‐induced acute pancreatitis
Authors: Bergholm U. , Langman M. , Rawllins M. , Gaist D. , Andersen M. , Edwards I. R. , Wiholm B.‐E. 
Published: October 2006

AbstractThe incidence of acute pancreatitis appears to have increased in the USA, Denmark and in the United Kingdom and one suggested explanatory factor is a simultaneously increased use of certain drugs.This report surveys the available information on the association between drugs and acute pancreatitis in the literature and in spontaneous reporting systems in Denmark, Sweden and in the United Kingdom, supplemented with information from the WHO data base.Apart from one case‐control study which provided evidence for an association between diuretic use and acute pancreatitis, the information in the literature is based on single case reports. About 15 drugs are frequently reported both in literature, and in spontaneous reporting systems, to be associated with pancreatitis and can be regarded as adverse reaction signals. The validity of such data is often low and does not provide information on relative or absolute risks, if any, for a drug adverse reaction association.To elucidate the possible role of drugs in etiology of acute pancreatitis, further formal epidemiologic studies are needed.
Synthesis and MALDI‐TOF analysis of dendritic‐linear block copolymers of lactides: Influence of architecture on stereocomplexation
Authors: Richez Alexandre , Belleney Joel , Bouteiller Laurent , Pensec Sandrine 
Published: October 2006

AbstractFormation of a stereocomplex from polylactide copolymers can be tuned by changing the size and the chain topology of the second block in the copolymer. In particular, the use of a dendritic instead of linear architecture is expected to destabilize the cocrystallisation of polylactide blocks. With this idea in mind, dendritic‐linear block copolymers were synthesized by ring‐opening polymerization (ROP) of lactides using benzyl alcohol dendrons of generation 1–3 as macroinitiators and stannous octoate as catalyst. Polymers with controlled and narrow molar mass distribution were obtained. The MALDI‐TOF mass spectra of these dendritic‐linear block copolymers show well‐resolved signals. Remarkably, 10% or less of odd‐membered polymers are present, indicating that ester‐exchange reactions which occur classically parallel to the polymerization process, were in these conditions, very limited. Thermal analysis of polyenantiomers of generation 1–3 and the corresponding blends were examined. The blend of a pair of enantiomeric dendritic‐linear block copolymers exhibit a higher melting temperature than each copolymer, characteristic for the formation of a stereocomplex. Melting temperatures are strongly dependent on the dendron generation. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6782–6789, 2006
In situ electron spin resonance study of styrene grafting of electron irradiated fluoropolymer films for fuel cell membranes
Authors: Mitov Svetlin , Hübner Gerold , Brack Hans‐Peter , Scherer Günther G. , Roduner Emil 
Published: October 2006

AbstractThree different electron beam irradiated fluoropolymers (ETFE, FEP, and PVDF) as well as their grafting reactions with styrene in different diluents were investigated by means of electron spin resonance (ESR). Depending on the atmosphere during irradiation, ESR spectra of peroxy and alkyl radicals were observed. Radical decay as a function of time and temperature was investigated in the presence and absence of solvent. Grafting levels and number of monomer units per chain were calculated for both types of radicals. Irradiation atmosphere, grafting temperature, and added solvent affect the morphology of the fluoropolymers, in particular the crystalline versus amorphous fractions and their swelling. They thus influence the rate at which the initial radicals at the polymer backbone are reached during the grafting process. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3323–3336, 2006
Antileishmanial activity of harmaline and other tryptamine derivatives
Authors: Evans A. Tudor , Croft Simon L. 
Published: October 2006

AbstractTryptamine derivatives harmaline and α‐ethyltryptamine were found to possess a novel antiparasitic action against human pathogen Leishmania mexicana amazonensis both in vitro and in vivo. In vitro, harmaline was the most potent compound tested, with an ED50 of 99μ, whilst α‐ethyltryptamine (ED50 149 μ) had the best therapeutic index (2). In vivo, α‐ethyltryptamine was most effective when given orally (ED50 47 mg/kg), but was also effective when given topically. We suggest that further investigation of traditional plant drugs containing derivatives of β‐carbolines and alkyltryptamines would provide a number of novel antiparasitic drugs.
Enhancement of adipose differentiation of mouse 3T3‐L1 fibroblasts by ginsenosides
Authors: Sekiya Keizo , Okuda Hiromichi , Hotta Yasuo , Arichi Shigeru 
Published: October 2006

AbstractSome ginsenosides, extracted and purified from the roots of Panax ginseng C. A. Meyer, stimulated adipose differentiation of mouse 3T3‐L1 fibroblasts. Ginsenoside Rb1 induced adipose differentiation of 3T3‐L1 cells in a culture medium supplemented with 20% fetal calf serum, but not in one with 10% fetal calf serum. Furthermore, ginsenoside Rb1 enhanced adipose differentiation induced by insulin or dexamethasone plus 1‐methyl‐3‐isobutylxanthine (DEX‐MIX). Other ginsenosides such as ginsenoside Rd and Rh2 also enhanced DEX‐MIX‐induced adipose differentiation, but ginsenosides Re, Rg1 and Ro had no effect. These results suggest that there is a clear structure‐activity relationship to the 20(S)‐protopanaxadiol aglycone group only in stimulation of adipose differentiation.
Pharmacological analysis of the inhibitory effect of jatrophone, a diterpene isolated from Jatropha elliptica, on smooth and cardiac muscles
Authors: Calixto João B. , Sant'Ana Antonio E. G. 
Published: October 2006

AbstractThe present work was conducted to analyse the effect of the diterpene jatrophone on drug and electrically evoked contractions of cardiac and smooth muscle preparations. Pre‐incubation of the isolated rat uterus with jatrophone (1–100 μM), for 20 min caused a decrease in the maximal contractions and a rightward displacement of the dose‐response curves to acetylcholine, bradykinin, and oxytocin. In the isolated longitudinal muscle from guinea‐pig ileum, jatrophone (1.6–12.8 μM) produced a concentration‐dependent inhibitory effect of acetylcholine, bradykinin and histamine‐induced contractions. In this tissue, jatrophone was about 5 to 8‐fold more potent in inhibiting acetylcholine and bradykinin than in uterine muscle. In strips of guinea‐pig ileum, guinea‐pig urinary bladder, rat left atrium electrically stimulated, and dog ureter contractions, jatrophone (1–100 μM) caused a concentration‐dependent inhibitory effect. In preparations electrically stimulated, jatrophone was about 2.5 to 23‐fold less potent compared to those values obtained against agonist‐induced contractions in the guinea‐pig ileum. These results demonstrate that jatrophone exerts direct inhibitory effect on cardiac and smooth muscle preparations and show that its inhibitory potency may vary according to the tissue and/or stimulus employed to induce muscle contractions.
Pharmacological Investigation on Sodium Salt and Acetyl Derivative of Anacardic Acid
Authors: Bhattacharya Salil K. , Mukhopadhyay Meeta , Rao Patchala J. R. Mohan , Bagchi Anjana , Ray Anil B. 
Published: October 2006

AbstractSodium salts of anacardic acid (SA) and O‐acetyl anacardic acid (AA) were subjected to pharmacological screening primarily on paradigms known to be affected by prostaglandin (PG) synthesis inhibitors. Results were compared with those elicited by known cyclo‐oxygenase inhibitors. SA and AA had little discernible effect on general behaviour and showed overt signs of central stimulation in unusually large doses. SA augmented spontaneous motor activity in mice and attenuated hexobarbitone hypnosis in rats. It augmented the convulsant action of pentylene‐tetrazol and inhibited the anticonvulsant effect of phenobarbitone against maximal electroshock‐induced seizures in rats. SA inhibited catalepsy induced by morphine and haloperidol in rats, and antagonized bradykinin‐induced catalepsy when administered intracerebroventricularly (i.c.v.) in rats. Both exhibited significant anti‐inflammatory activity against carrageenin‐induced acute inflammation in rats. This anti‐inflammatory effect was also in evidence when SA was administered i.c.v. SA and AA had no per se effect on rectal temperature in rats but significantly attenuated the hyperthermia induced by i.c.v. bradykinin or i.p. carrageenin. In all these parameters the effects of SA or AA were comparable to those elicited by diclofenac, aspirin or acetaminophen. However, unlike aspirin and diclofenac, which showed significant antinociceptive activity against phenylquinone‐induced writhing technique, SA was additionally effective against radiant heat and thermic stimulation‐induced nocisponsive technique. Both SA and AA appeared to be fairly safe drugs as assessed by acute toxicity studies. Like the cyclo‐oxygenase inhibitor, diclofenac, SA significantly reduced rat brain PGE2 and PGF2α concentrations, as assessed by a radioimmunoassay technique. Pharmacological and biochemical studies indicate that anacardic acid functions as a PG synthesis inhibitor, with the added advantage of having a central analgesic property.
The cellular actions of the avermectins
Authors: Wann Kenneth T. 
Published: October 2006

AbstractIvermectin is a synthetic derivative of the naturally occurring fermentation products, the avermectins. It was introduced as an antiparasitic drug in 1981, is now widely used in many countries, and as a drug has attracted considerable attention. In veterinary medicine its broad spectrum of activity has proved invaluable. In clinical trials in man its action seems to surpass that of currently available alternatives. The putative mode of action of the avermectins (AVMs) is unique, and this action has prompted within the industry a rethink of current strategies and a search for new drugs with equal activity. As tools the AVMs are also sufficiently refined to permit detailed probing of the properties of the GABA receptor channels of both mammalian and non‐mammalian systems. Consequently our knowledge of such systems has been enhanced by the judicious use of these probes. In this review the principal cellular actions of the AVMs are discussed. These actions provide insight into the possible mechanisms underlying the potent biological activity displayed by these agents.
Activation of immunoresponder cells by the protein fraction from aged garlic extract
Authors: Hirao Yuzo , Sumioka Isao , Nakagami Satoru , Yamamoto Michiko , Hatono Syunzo , Yoshida Susumu , Fuwa Tohru , Nakagawa Shizutoshi 
Published: October 2006

AbstractF‐4, a protein fraction isolated from aged garlic extract strongly stimulates mice peritoneal macrophages in terms of glucose utilization and exhibits cytostatic activity in vitro. F‐4 also has a mitogenic activity on spleen cells. In vivo, F‐4 induced the stimulation of carbon clearance activity in mice. No obvious activities were observed in the low molecular fraction of aged garlic in these tests, but weak effects were found in the fructan fraction (F‐3).
Structural role of an unsaturated lactone in acute toxicity of rubratoxin B isolated from Penicillium rubrum
Authors: Feng Y. P. , Wong S. M. , Evans M. A. 
Published: October 2006

AbstractRubratoxin B is a substituted higher homolog of byssochlamic acid in which the ethyl group is replaced by a six‐membered ring containing an unsaturated lactone. Hydrogenation of the unsaturated lactone greatly reduces the acute toxixity of the compound. The acute median lethal doses of rubratoxin B and hydrogenated rubratoxin in male mice were 5.6 and 31 mg/kg, respectively. Pretreatment with phenobarbital (60 rag/kg × 4 days) or with SKF 525A (40 mg/kg) failed to significantly alter the toxicity of either compound. Histopathological examination of mice treated with rubratoxin B (3.5 mg/kg) revealed areas of hepatic zonal necrosis and marked necrosis of kidney tubules. No necrosis was observed in mice treated with hydrogenated rubratoxin (20 mg/kg). Hepatic microsomal mixed function oxidase activity was significantly reduced in mice pretreated with rubratoxin B (0.5 mg/kg × 4 days), while pretreatment with hydrogenated rubratoxin (2.5 mg/kg × 4 days) failed to depress microsomal activity. Our studies document the requirement of an alpha, beta unsaturated lactone ring for rubratoxin B toxicity. Based on the results from these studies the mechanism for rubratoxin B induced toxicity is postulated to be due to its electrophilic properties and subsequent alkylating activity.
Effects of chalcones isolated from licorice roots on leukotriene biosynthesis in human polymorphonuclear neutrophls
Authors: Kimura Yoshiyuki , Okuda Hiromichi , Okuda Takuo , Arichi Shigeru 
Published: October 2006

AbstractThe effects of chalcones and flavanones isolated from Sinkiang Licorice (Glycyrrhiza inflata Bat.) on leukotriene B4(LTB4) and C4(LTC4) formation in human polymorphonuclear neutrophils (PMNs) were investigated. Licochalcone A (2‐methoxy‐4,4′‐dihydroxy‐5‐α,α‐dimethyl‐allylchalcone) and licochalcone B (2‐methoxy‐3,4,4′‐trihydroxychalcone), at concentrations of 10−3 to 10−6 M, inhibited calcium ionophore A 23187 (A 23187)‐induced LTB4 and LTC4 formation in human PMNs. The concentration of licochalcones A required for 50% inhibition (LC50) of LTB4 and LTC4 formation was 4.6 × 10−7 and 4.2×10−6 M, respectively, using 2 μM A 23187. The IC50 values of licochalcone B for LTB4 and LTC4 formation were also 1.2 × 10−6 and 2.0×10−6 M, respectively. In addition, licochalcones A and B significantly increased cyclic AMP level in human PMNs at concentrations of 10−4 to 10−3 M. Licochalcones A and B were found to reduce the elevation of the cytosolic free calcium concentration induced by calcium ionomycine, dose‐dependently, in the presence of 1 mM Ca2+ or 1 mM EGTA.
Mechanisms of hypoglycemic activity of panaxans A and B, glycans of Panax ginseng roots: Effects on plasma level, secretion, sensitivity and binding of insulin in mice
Authors: Suzuki Yutaka , Hikino Hiroshi 
Published: October 2006

AbstractPanaxan A did not affect plasma insulin levels and insulin sensitivity, whereas Panaxan B elevated the plasma insulin level and enhanced insulin sensitivity in vivo. When mice were treated with panaxan B, insulin secretion from pancreatic islets was potentiated, while direct addition of panaxan B to pancreatic islets from normal mice showed no enhancement of insulin secretion in vitro. Hypoglycemic activity of panaxan B was not inhibited by indomethacin. Panaxans A and B showed hypoglycemic activity in spontaneously diabetic mice. Insulin binding to isolated adipocytes obtained from panaxan B‐treated mice was significantly increased, while direct addition of panaxan B to isolated adipocytes from normal mice elicited no increase of insulin binding. It is concluded that a part of the hypoglycemic activity of panaxan B is due to increase of the plasma insulin level and enhancement of insulin sensitivity, while that of panaxan A is attributable to other mechanisms.