bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of xylem translocation of weak electrolytes with the pressure chamber technique
Authors: Ciucani Giovannella , Trevisan Marco , Sacchi Gian Attilio , Trapp Stefan A J 
Published: August 2002

AbstractXylem translocation and root uptake of weak electrolytes were investigated with the pressure chamber technique (PCT) using de‐topped soybean plants. Two compounds were organic bases (fenpropimorph and imazalil) and four were organic acids (bentazone, primisulfuron‐methyl, rimsulfuron and triasulfuron). The compounds covered a wide range of log KOW and pKa values. Concentrations in external solution and in xylem sap were measured by HPLC at pH values in external solution of 4.5, 6.5 and 8.5. For weak bases, translocation was higher at low pH and the transpiration stream concentration factors (TSCF) were in the range 0.31–0.95. At pH 8.5, the concentrations in leaking xylem sap were very low for fenpropimorph, and steady‐state was probably not reached. For weak acids, TSCF values derived with external pH from 4.5 to 8.5 were in the range 0.55–1.50 for primisulfuron‐methyl, 0.64–1.35 for rimsulfuron, 0.81–0.93 for triasulfuron and 0.69–0.92 for bentazone. The variation of TSCF of the weak electrolytes was much smaller in these PCT experiments than in recent experiments with intact plants. The likely reason is that de‐topped soybean plants in the pressure chamber seemed to be unable to regulate their xylem sap pH, which was almost identical to the pH in external solution. Without pH differences, the ion‐trap process, which is responsible for accumulation or exclusion of weak acids and bases in the xylem of living plants, does not take place. Model simulations carried out for intact and de‐topped plants supported this hypothesis. By variation of the pH of the xylem sap, good agreement between measurements and simulations could be achieved.© 2002 Society of Chemical Industry
Solid‐phase synthesis of cyclic analogues related to the hypoglycaemic peptide hGH[6–13]: Comparison of two i→i+4 lactam cyclization procedures
Authors: Cavallaro Vittoria , Thompson Philip E. , Hearn Milton T.W. 
Published: August 2002

AbstractThe use of 1,3‐diisopropylcarbodiimide (DIC) for the synthesis of cyclic analogues of the hypoglycaemic peptide fragment derived from the N‐terminus of human growth hormone (hGH), namely hGH[6–13], is described. Different strategies were examined to achieve improved yields for the on resin side‐chain to side‐chain cyclization of the corresponding linear peptides containing reverse β‐turn motifs. When compared with the more reactive Castro's reagent, the results confirm that DIC in the presence of HOBt can be successfully employed to minimize the formation of intermolecular oligomeric by‐products associated with the preparation of cyclic hGH[6–14] peptide analogues based on an i→(i+4)Lys→Glu or Glu→Lys cyclization strategy. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
An alternative solid phase peptide fragment condensation protocol with improved efficiency
Authors: Mihala Nikolett , Bódi József , Gömöry Ágnes , Süli‐Vargha Helga 
Published: August 2002

AbstractThe success of solid phase peptide synthesis is often limited by the aggregation of the growing peptide chains on the resin. Working from the results of a study of model coupling reactions in solution between Z‐Gly‐Phe‐OH and H‐Phe‐OBzl, we have achieved higher efficiency in the repetitive solid phase fragment condensation of VGVAPG, in a 3:1 chloroform‐phenol solvent system, using diisopropylcarbodiimide (DIC) as coupling agent, and a combination of 3‐hydroxy‐3,4‐dihydro‐4‐oxo‐1,2,3‐benzotriazine (HODhbt) and its tetrabutyl ammonium salt as additive, than in DMF with DIC and HODhbt alone. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
Kava kava in the treatment of generalized anxiety disorder, simple phobia and specific social phobia
Authors: Boerner R. J. 
Published: August 2002

AbstractA 37‐year‐old female outpatient with generalized anxiety disorder, a simple phobia and a specific social phobia was treated with phytotherapy (Kava kava). Within 4 weeks, symptoms had improved by 75% and by 6 months an almost total remission of symptoms was observed. The herbal medicine was well tolerated. Kava has considerable potential value in the treatment of anxiety disorders. Copyright © 2001 John Wiley & Sons, Ltd.
Cellular pharmacology studies of shikonin derivatives
Authors: Chen Xin , Yang Lu , Oppenheim Joost J. , Howard O. M. Zack 
Published: August 2002

AbstractThe naphthoquinone pigment, shikonin, isolated from Lithospermum erythrorhizon Sieb. et Zucc.(Boraginaceae) and its derivatives are the active components isolated from the Chinese herbal therapeutic, Zicao. Historically, Zicao root extracts have been used to treat macular eruption, measles, sore‐throat, carbuncles and burns. Multiple pharmacological actions have been attributed to shikonin, e.g. antiinflammatory, antigonadotropic and anti‐HIV‐1 activity. In this review, several therapeutic applications of shikonin will be summarized including its pleiotropic, antiinflammatory and antitumour effects. Widely diverse and sometimes conflicting activities have been attributed to shikonin, e.g. wound healing, enhanced granuloma formation, suppression of local acute inflammatory reactions, inhibition of angiogenesis, inhibition of select chemokine ligands, inhibition of DNA topoisomerase activity, inhibition of platelet activation and antimicrobial activity. Comparison of the various reported mechanisms of action for shikonin lead us to hypothesize that shikonin is an effective inhibitor of protein–protein interaction with multiple targets in both the intracellular and extracellular compartments. This general inhibitory effect can account for the broad spectrum of shikonin biological and pharmacological activities.
Published in 2002 by John Wiley & Sons, Ltd.
In vitro Leishmanicidal activity of naturally occurring chalcones
Authors: Kayser Oliver , Kiderlen Albrecht F. 
Published: August 2002

AbstractA variety of chalcones have been shown to exhibit activity against Leishmania parasites. In contrast to synthetic or semisynthetic chalcones, only a few plant‐derived compounds have been investigated. To provide a scientific rational for the antiprotozoal potency of plants used in ethnomedicine and containing chalcones, and in the search for new antiprotozoal drugs, we have carried out a primary screening for in vitro leishmanicidal activity of 20 chalcones isolated from plants. The compounds were tested against extracellular promastigotes of Leishmania donovani, L. infantum, L. enrietii and L. major, and against intracellular amastigote L. donovani residing within murine macrophages. Against the extracellular Leishmania (L. donovani), most compounds were active with EC50 values between 0.07 and 2.01 µg/mL. Some of these chalcones, 2′,4′‐dihydroxy‐4‐methoxychalcone, 2′‐hydroxy‐3,4‐dimethoxychalcone and 2‐hydroxy‐4,4′‐dimethoxychalcone also significantly inhibited the intracellular survival of L. donovani parasites with EC50 values between 0.39 and 0.41 µg/mL. When tested against murine bone marrow‐derived macrophages as a mammalian host cell control, all compounds with antileishmanial activities also proved to be cytotoxic to varying extents (EC50 0.19–2.06 µg/mL). Correlations between molecular structures and antileishmanial activity are discussed in detail. Specific compounds are illustrated with emphasis on their mode of action and potential for the development of selective antiprotozoal agents. Copyright ­© 2001 John Wiley & Sons, Ltd.
The effect of capsaicin on blood glucose, plasma insulin levels and insulin binding in dog models
Authors: Tolan I. , Ragoobirsingh D. , Morrison E. Y. St. A. 
Published: August 2002

AbstractCapsicum frutescens has been used to treat diabetes mellitus by traditional healers in Jamaica. This study was designed to identify any hypoglycaemic principle(s) and to determine the mechanism of action. Purification experiments employing thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) led to the extraction of the active principle, capsaicin. Capsaicin caused a decrease in blood glucose levels of 4.91 ± 0.52 (n = 6) mmol/dL versus 6.40 ± 0.13 mmol/dL (n = 6) for the control (p < 0.05) at the 2.5 h time interval when the oral glucose tolerance test (OGTT) was performed on dogs treated with capsaicin and compared with the control. Plasma insulin levels measured at the 2.5 h time interval showed that there was an increase in plasma insulin levels of 5.78 ± 0.76 µIU/mL (n = 6) for the capsaicin treated dogs versus 3.70 ± 0.43 µIU/mL (n = 10) for the control (p < 0.05). Insulin receptor studies, using a modification of the method of Gambhir et al. done on monocytes obtained from blood at the 2.5 h time interval showed that there was a decrease in the percentage receptor binding for the capsaicin treated dogs when compared with the control. Insulin affinity results showed that there was a decrease of 2.4 × 10−4 in monocytes for the capsaicin treated dogs versus 8.77 × 10−4 for the control (p < 0.05). Also, insulin receptor calculations showed a decrease in number, 2.63 × 108 ± 5.73 × 107, compared with 8.77 × 108 ± 1.47 × 108 for the control. In conclusion it can be stated that capsaicin is responsible for the hypoglycaemic episodes seen in the dogs and that it also causes an increase in insulin secretion which leads to a reduction of insulin binding on the insulin receptors. Copyright © 2001 John Wiley & Sons, Ltd.
Antimicrobial activity of seed extracts and bondenolide from Caesalpinia bonduc (L.) Roxb.
Authors: Simin K. , Khaliq‐uz‐Zaman S. M. , Ahmad V. U. 
Published: August 2002

AbstractThe antibacterial and antifungal activities, along with a phytotoxicity test of the newly isolated diterpene bondenolide (1), of a methanol extract, ethylacetate fraction and water soluble part of the methanol extract of Caesalpinia bonduc (L.) Roxb. were assayed. Copyright © 2001 John Wiley & Sons, Ltd.
LDH profiles of male and female rats treated with Vepacide
Authors: Rahman M. F. , Siddiqui M. K. J. , Jamil Kaiser 
Published: August 2002

AbstractIn the present study we investigated the effect of vepacide, a neem‐based compound, on the biochemical target enzyme lactate dehydrogenase (LDH) in different tissues of male and female albino Wistar rats treated orally with 80, 160 and 320 mg/kg (low, medium and high doses, respectively) for a period of 90 days. Prolonged administration of vepacide caused a significant increase of LDH activity in serum and lung tissues and a decrease in liver and kidney in both male and female rats when measured after 45 and 90 days of daily treatment. Females were more susceptible than males with regard to serum and kidney LDH showing sexual dimorphism in the treated rats. Recovery was observed in the affected enzyme after 28 days post treatment (withdrawal study). A positive correlation was observed with regard to this enzyme between serum and lung tissues, whereas for serum versus liver and kidney there was a negative correlation. The effect of vepacide was more pronounced in the lung tissue followed by liver and kidney tissues. Necrosis of the liver and kidney tissues was observed but in the lung tissue an increase in the LDH enzyme was seen. Therefore, it was concluded that the increase in LDH could be indicative of a stress adaptive response to the toxicant. Copyright © 2002 John Wiley & Sons, Ltd.
The antiulcer activity of Garcinia cambogia extract against indomethacin‐induced gastric ulcer in rats
Authors: Mahendran P. , Vanisree A. J. , Shyamala Devi C. S. 
Published: August 2002

AbstractGarcinia cambogia extract is a herbal preparation that has been suggested as useful in the treatment of gastrointestinal disorders. In the present study this drug was tested for its antiulcerogenic effect. Oral pretreatment with Garcinia cambogia fruit extract (1 g/kg body wt/day) for 5, 10 or 15 days protected the gastric mucosa against the damage induced by indomethacin (20 mg/kg body wt). The volume and acidity of the gastric juice decreased in the pretreated rats. The glycoprotein levels of the gastric contents which were decreased in the untreated rats, maintained near normal levels in the pretreated rats. Protein which was elevated in the gastric juice of untreated rats, showed near normal levels in the pretreated rats. Garcinia cambogia was able to decrease the acidity and to increase the mucosal defence in the gastric areas, thereby justifying its use as an antiulcerogenic agent. Copyright © 2002 John Wiley & Sons, Ltd.
ISO 9002 certification – expectations of the sponsor's auditor
Authors: Widler Beat 
Published: August 2002

AbstractThe value of ISO standards or rather the reliability of their application by clinical laboratories and CROs must be questioned. Results from audits performed by auditors overseeing ISO certification and maintenance do not necessarily provide full confidence in the ISO certification process to sponsors. Based on our sponsor‐audits, we concluded that an ISO certification cannot substitute a systems' audit conducted by our own auditors against GCP and, where appropriate, GLP standards. Copyright © 2002 John Wiley & Sons, Ltd.
GLPs and medical devices
Authors: Lynn Linda Palagi 
Published: August 2002

AbstractApplying Good Laboratory Practice (GLP) regulations to studies of medical devices and combination products (drug/device products) presents some unique challenges. The complexity of medical devices – which may be internal, external, or composed of many intricate parts including software, hardware, or drugs to perform their intended task – requires interpretation of the regulations. Further, the dynamics of the conduct of non‐clinical laboratory studies for medical devices can be quite complex often involving a team of scientists, engineers, computer specialists, technicians, veterinarians, physicians, pathologists and equipment from both the test facility and sponsor. This article highlights areas of the GLP regulations and provides information and suggestions for GLP compliance for medical device studies. Copyright © 2002 John Wiley & Sons, Ltd.
Dynamics of primary charge separation in bacterial photosynthesis using the multilevel Redfield–Davies secular approach
Authors: Sadygov Rovshan G. , Neuhauser Daniel 
Published: August 2002

AbstractWe use Redfield's relaxation theory in the Davies formulation to study primary charge separation reactions in bacterial photosynthesis. The specific model studied is the standard one (spin‐boson), with three states for the system, harmonic oscillators for the bath, and linear ohmic system–bath coupling. The Redfield–Davies formulation, which is equivalent to the secular approximation, is Markovian, of second order in system–bath coupling, and is written for the system's density matrix. The approximation does not suffer from any negative probabilities (which appear in the original Redfield approach) and can therefore be used for long‐time processes (20 ps or more here). Our results are in line with previous studies, especially to high bath frequencies. They confirm the usefulness of the Redfield–Davies secular approach as a convenient and simple tool for studying system–bath processes. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem, 2002
Mechanism of action of zinc proteinases: A MNDO/d/H study of alternative general‐acid general‐base catalytic pathways for carboxypeptidase‐A
Authors: Kilshtain‐Vardi Alexandra , Shoham Gil , Goldblum Amiram 
Published: August 2002

AbstractTwo alternative pathways for peptide cleavage by water, both of the general‐acid general‐base type, have been followed by semiempirical theoretical calculations on a model of the active site. The system of 120 atoms has been carved out of high resolution X‐ray coordinates of a carboxypeptidase A (CPA) complex with a ketomethylene inhibitor, pyroglutamic‐N‐Phe‐(CH2CO)‐Phe‐OH. The method employed was a combination of MNDO/d and MNDO/H which, together, enable one to deal with the effect of zinc and of multiple hydrogen bond interactions, respectively. The first step in both pathways is nucleophilic attack by a hydroxide on the peptide carbonyl, and the second is proton transfer to the nitrogen of the peptide. This second step presents the highest energy barrier for the reaction. Peptide bond cleavage is spontaneous subsequent to proton transfer. The two alternative paths differ little in barrier heights, but the thermodynamic enthalpy difference for the path of one mechanism is some 20 kcal/mol more stable than for the other. The first mechanism is the one proposed by Lipscomb (Acc Chem Res 1989, 22, 62–69) and the second, less stabilizing mechanism was proposed by Mock (J Biol Chem 1991, 266, 6369–6400). Under kinetic control, both reactions are feasible, and new experiments should be designed in order to clarify if only one of the two is operating under most of the relevant conditions. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem 88: 87–98, 2002
Why does 5‐methylchrysene interact with DNA as both a planar and a nonplanar polycyclic aromatic hydrocarbon? Quantum mechanical studies
Authors: Rabinowitz James , Little Stephen , Brown Katrina 
Published: August 2002

AbstractPolycyclic aromatic hydrocarbons are a large class of anthropogenic chemicals found in the environment. Some class members are potent animal carcinogens while other similar class members show little carcinogenic activity. When considering a series of in vitro studies of the interaction of polycyclic aromatic hydrocarbon bay region diol‐epoxides with deoxyribonucleic acid (DNA), it was found that molecules with a crowded bay region behaved differently than molecules with a more open bay region. Molecules with a crowded bay region are nonplanar while in general polycyclic aromatic hydrocarbons are planar molecules. This dichotomy between planar and nonplanar subclasses proved useful, but when the experimental data was considered, 5‐methylchrysene did not fit well into either class. In this study quantum mechanical calculations are reported that show 5‐methyl chrysene and its diol‐epoxides are nonplanar molecules, but the energy required to force them to be planar is considerably smaller than for most other nonplanar polycyclic aromatic hydrocarbons. The relationship to the experimental results that indicated 5‐methylchrysene may behave like both a planar polycyclic aromatic hydrocarbon in some experiments and a nonplanar polycyclic aromatic hydrocarbon in others is discussed. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem, 2002
Photoabsorption processes in nitrous oxide and formaldehyde
Authors: Martín I. , Velasco A. M. , Lavín C. , Olalla E. , Bustos E. 
Published: August 2002

AbstractAbsorption oscillator strengths and photoionization cross sections for electronic transitions involving Rydberg states that are relevant to the photochemistry of N2O and H2CO are reported. These compounds have been found to play an important role in the evolution of Earth's upper atmosphere. However, the difficulties encoutered in both laboratory measurements and theoretical calculations on the photoabsorption of these compounds are responsible for the scarcity of data in the literature. The present calculations have been performed with the molecular‐adapted quantum defect orbital (MQDO) method, of which the adequacy for this type of studies has recently been assessed. A comparative analysis of the photoabsorption intensities in the molecules and their constituting atoms has enabled us to predict the variation of the extent of atomic character of the molecular Rydberg orbitals with the degree of excitation. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Rapid and sensitive quantitation of antibiotics in fermentations by electrospray mass spectrometry
Authors: Morgan Janine , Joyce‐Menekse Miranda E. , Rowlands Robert T. , Gilbert Ian H. , Lloyd David 
Published: August 2002

AbstractElectrospray ionisation mass spectrometry (ESI‐MS) has been used for the determination and quantitation of a broad range of 24 antibiotics, from groups including aminoglycosides, β‐lactams, tetracyclines, antifungals and glycopeptides. Spectra have been acquired for all 24 antibiotics derived from pure samples dissolved in acetonitrile/water, along with samples extracted from complex fermentation liquor. Quantitation was carried out by the detection of the protonated molecules, using time‐scheduled single‐ion monitoring (SIM). ESI‐MS was used to detect and quantify to 5‐µM levels. A one‐step extraction of antibiotics with an organic solvent (methanol) was used for this rapid and simple procedure. Specificity is not matched by other methods and antibiotic analogues (e.g. the five forms of erythromycin) can be determined within minutes. Copyright © 2001 John Wiley & Sons, Ltd.
Characterisation of anthocyanidins by electrospray ionisation and collision‐induced dissociation tandem mass spectrometry
Authors: Oliveira M. C. , Esperança P. , Almoster Ferreira M. A. 
Published: August 2002

AbstractThe present study describes the use of electrospray ionisation mass spectrometry, in combination with collision‐induced dissociation (CID) and tandem mass spectrometry, for the structural characterisation of anthocyanidins and their O‐glycosides. The high‐energy CID spectra of [M−Cl]+ ions of the free aglycones show characteristic fragmentation pathways, which provide useful information about the substitution pattern in the A‐ and B‐rings of each compound. The major fragmentation observed in the high‐energy CID spectra of [M−Cl]+ ions of anthocyanins involves loss of the mono‐ or disaccharide units resulting in ions containing only the aglycone moiety. From the spectral data, the identity of the aglycone can be established as well as the number and the class of monosaccharide units in the O‐glycosides. Copyright © 2001 John Wiley & Sons, Ltd.
Automatic function switching and its usefulness in peptide and protein analysis using direct infusion microspray quadrupole time‐of‐flight mass spectrometry
Authors: Hoyes Emmy , Gaskell Simon J. 
Published: August 2002

AbstractAutomatic function switching has been investigated for high‐throughput protein identification and sequencing of peptides using direct infusion of tryptic digests on a quadrupole time‐of‐flight instrument. The increase in speed and the high quality of data make it a favourable technique for tandem mass spectrometry when compared to manual selection of each precursor ion; these advantages are not restricted to combined LC/MS/MS analyses for which the automatic function‐switching mode was originally developed. This mode was compared to analyses performed using a slow scan of the quadrupole analyzer with repeated recording of product ion spectra. For the specific purpose of generating product ion data for sequence determination (as opposed to surveying all precursors of a selected product ion), the automatic function‐switching mode was, as expected, markedly superior with respect to speed of analysis and quality of data. Furthermore, the automatic function‐switching mode provides greater versatility with respect to selection of optimal collision energies. Copyright © 2001 John Wiley & Sons, Ltd.