Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 12 de 12
Filter
Add more filters










Publication year range
1.
Eur J Sport Sci ; 18(1): 123-129, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29231092

ABSTRACT

The irrational performance beliefs inventory (iPBI) was developed to measure irrational beliefs within performance domains such as sport, academia, business, and the military. Past research indicates that the iPBI has good construct, concurrent, and predictive validity, but the test-retest reliability of the iPBI has not yet been examined. Therefore, in the present study the iPBI was administered to university sport and exercise students (n = 160) and academy soccer athletes (n = 75) at three-time points. Time point two occurred 7 days after time point one, and time point three occurred 21 days after time point two. In addition, social desirability was also measured. Repeated-measures MANCOVAs, intra-class coefficients, and Pearson's (r) correlations demonstrate that the iPBI has good test-retest reliability, with iPBI scores remaining stable across the three-time points. Pearson's correlation coefficients revealed no relationships between the iPBI and social desirability, indicating that the iPBI is not highly susceptible to response bias. The results are discussed with reference to the continued usage and development of the iPBI, and future research recommendations relating to the investigation of irrational performance beliefs are proposed.


Subject(s)
Athletes/psychology , Students/psychology , Academic Performance/psychology , Adolescent , Athletic Performance/psychology , Female , Humans , Male , Physical Education and Training , Psychological Tests , Reproducibility of Results , Soccer , Young Adult
2.
Fish Physiol Biochem ; 43(6): 1501-1515, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28798999

ABSTRACT

Immunostimulants are widely applied in aquaculture practice and may have beneficial effects on the immune system and physical functions allowing higher tolerance to stress. In the current study, the impact of four (i-iv) dietary active ingredients on the immune and stress response of turbot was examined in two experiments (I and II). A basal low fish meal (FM; 32%) diet was formulated and supplemented with (i) yeast ß-glucan and mannan oligosaccharide (GM), (ii) alginic acid (AC), (iii) yeast nucleotides and RNA (NR), or (iv) Bacillus strains (BS). The basal diet (C-LF) and a high FM (59%) control (C-HF) were maintained. All six diets were fed to juvenile turbots for 84 days in experiment I and for additional 28 days prior to experiment II. Immunological and hematological parameters were determined in experiment I. In experiment II, physical stress response to a typical short-term (<1 day) aquaculture handling procedure (combination of capture, netting/transfer, and crowding) was investigated. For this, turbot blood was sampled before and at 0.5, 1, 4, and 24 h post stress. Plasma lysozyme activity, neutrophil reactive oxygen species (ROS) production, and total plasma protein levels did not significantly differ between treatment groups; however, plasma cholesterol increased significantly in fish fed GM, AC, NR, and C-HF compared to C-LF (I). A significant increase in plasma glucose and triglyceride was observed in GM and NR treatments, while glucose levels were significantly higher in C-HF compared to C-LF. Moreover, the immunostimulant-supplemented diets exhibited significantly lower cortisol levels compared to controls C-LF (at 0.5 h) and C-HF (at 1 h) post stress, respectively (II). According to our findings, FM substitution did not modulate the innate immune response but was associated with reduced levels of cholesterol. Dietary immunostimulants were not effective enough to boost the immune response, but we believe they might be helpful to trigger metabolic advantages during stressful handling events on fish farms.


Subject(s)
Bacillus/physiology , Flatfishes/physiology , Nucleic Acids/pharmacology , Polysaccharides/pharmacology , Stress, Physiological/drug effects , Animal Feed/analysis , Animal Nutritional Physiological Phenomena , Animals , Aquaculture , Diet/veterinary , Hydrocortisone/blood , Immunity, Innate/drug effects , Immunity, Innate/immunology , Polysaccharides/administration & dosage , Probiotics , Glycine max , Stress, Physiological/physiology , Triticum
3.
J Hazard Mater ; 125(1-3): 65-79, 2005 Oct 17.
Article in English | MEDLINE | ID: mdl-16081209

ABSTRACT

Extracting waterborne contaminants to ozone-loaded Volasiltrade mark245 (a siloxane solvent in which ozone is ten times more soluble than water) has been studied as a means of enhancing reaction kinetics and thus, providing more rapid wastewater decontamination. Investigation was carried out with respect to 2-chlorophenol and dichloromethane. Using a pilot scale continuous flow liquid-liquid/ozone water treatment system, 2-chlorophenol was extracted to the ozone-loaded solvent phase and considerable extents of destruction were achieved. However, the approach was demonstrated to yield slightly less destruction than direct gas contact for the same utilization of ozone and enhanced reaction kinetics were not shown to occur. This was suggested to be due to increased interfacial mass transfer resistance and/or the promotion of less destructive reaction pathways. Modification of the existing pilot system, by conversion from co- to counter-current solvent-loading, enabled greater dissolved ozone concentrations to be achieved within the solvent. Increasing the counter-current exchange column height to approximately 2.5m was suggested for achieving a near optimum level of performance. The liquid-liquid/ozone approach was demonstrated to be an effective means of indirectly exposing wastewater contaminants to concentrated ozone. As such the technology may be applicable as an alternative to direct gas contact in instances where the avoidance of contaminant sparging is desired (i.e. where contaminants are highly volatile, pungent and/or toxic) or foaming occurs.


Subject(s)
Chlorophenols/isolation & purification , Methylene Chloride/isolation & purification , Ozone/isolation & purification , Solvents/chemistry , Water Pollutants, Chemical/isolation & purification , Water Pollution, Chemical/prevention & control , Chlorophenols/chemistry , Equipment Design , Gases/chemistry , Kinetics , Methylene Chloride/chemistry , Oxidation-Reduction , Surface-Active Agents/chemistry , Water/chemistry
4.
Bioorg Med Chem Lett ; 11(15): 1993-5, 2001 Aug 06.
Article in English | MEDLINE | ID: mdl-11454465

ABSTRACT

The synthesis and antiviral evaluation of unsymmetrical indolocarbazole derivatives of Arcyriaflavin A, substituted with a range of alkyl groups at the indole nitrogen, is described. Structure-activity relationships in this series against human cytomegalovirus (HCMV) replication in cell culture are reported. Compound 4b was identified as potent inhibitor of HCMV (IC(50)=19 nM), which retained activity against a range of HCMV strains including ganciclovir resistant isolates.


Subject(s)
Antiviral Agents/chemical synthesis , Antiviral Agents/pharmacology , Carbazoles/pharmacology , Cytomegalovirus/drug effects , Indoles/pharmacology , Virus Replication/drug effects , Carbazoles/chemical synthesis , Cells, Cultured , Drug Resistance/genetics , Drug Resistance/physiology , Ganciclovir/pharmacology , Humans , Indoles/chemical synthesis , Inhibitory Concentration 50 , Protein Kinase C/antagonists & inhibitors , Structure-Activity Relationship
5.
Bioorg Chem ; 29(2): 77-95, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11300697

ABSTRACT

Phosphonamidates which bear a simple resemblance to penicillin type structures have been synthesised as potential inhibitors of beta-lactamases: -ethyl N-(benzyloxycarbonyl) amidomethyl phosphonyl amides, PhCH(2)OCONHCH(2)P(O)(OEt)NR(2), the amines HNR(2) being l-proline, d-proline, l-thiazolidine, and o-anthranilic acid. The proline derivatives completely and irreversibly inactivated the class C beta-lactamase from Enterobacter cloacae P99, in a time-dependent manner, indicative of covalent inhibition. The inactivation was found to be exclusive to the class C enzyme and no significant inhibition was observed with any other class of beta-lactamase. The anthranilic acid derivative exhibited no appreciable inactivation of the beta-lactamases. The phosphonyl proline and phosphonyl thioproline derivatives were separated into their diastereoisomers and their individual second order rate constants for inhibition were found to be 7.72 +/- 0.37 and 8.3 x 10(-2) +/- 0.004 M(-1) s(-1) for the l-proline derivatives, at pH 7.0. The products of the inhibition reaction of each individual diastereoisomer, analyzed by electrospray mass spectroscopy, indicate that the more reactive diastereoisomers phosphonylate the enzyme by P-N bond fission with the elimination of proline. Conversely, gas chromatographic detection of ethanol release by the less reactive proline diastereoisomer suggests phosphonylation occurs by P-O bond fission. The enzyme enhances the rate of phosphonylation with P-N fission by at least 10(6) compared with that effected by hydroxide-ion. The pH dependence of the rate of inhibition of the beta-lactamase by the more reactive diasteroisomer is consistent with the reaction of the diprotonated form of the enzyme, EH(2), with the inhibitor, I (or its kinetic equivalents EH with IH). This pH dependence and the rate enhancement indicate that the enzyme appears to use the same catalytic apparatus for phosphonylation as that used for hydrolysis of beta-lactams. The stereochemical consequences of nucleophilic displacement at the phosphonyl centre are discussed.


Subject(s)
beta-Lactamases/chemistry , Acylation , Algorithms , Anti-Bacterial Agents/metabolism , Catalysis , Chromatography, High Pressure Liquid , Enterobacter/enzymology , Hydrogen-Ion Concentration , Hydrolysis , Indicators and Reagents , Kinetics , Penicillin G/chemistry , Phosphorylation , beta-Lactamase Inhibitors
6.
Bioorg Med Chem Lett ; 10(7): 645-7, 2000 Apr 03.
Article in English | MEDLINE | ID: mdl-10762044

ABSTRACT

We describe a synthesis of acyclovir-5'-(phenyl methoxy alaninyl) phosphate (2) from acyclovir (1). This compound was designed to act as a lipophilic, membrane-soluble prodrug of the free nucleotide. However, the biological activities of this derivative against a range of viruses indicated poor intracellular phosphate delivery, in marked contrast to the earlier successful delivery of several dideoxy anti-HIV nucleotides.


Subject(s)
Acyclovir/analogs & derivatives , Antiviral Agents/chemical synthesis , Herpesvirus 2, Human/drug effects , Prodrugs/chemical synthesis , Acyclovir/chemical synthesis , Acyclovir/pharmacology , Animals , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Chlorocebus aethiops , Cytomegalovirus/drug effects , Herpesvirus 3, Human/drug effects , Prodrugs/chemistry , Prodrugs/metabolism , Prodrugs/pharmacology , Solubility , Vero Cells
7.
Bioorg Med Chem Lett ; 9(19): 2863-6, 1999 Oct 04.
Article in English | MEDLINE | ID: mdl-10522707

ABSTRACT

A random screening approach has identified 2-chloro-3-substituted-1,4-naphthoquinones as potent inactivators of HCMV protease. Enzyme inactivation is due to modification of Cys202. Two of the most potent compounds maintain activity against HCMV in a plaque reduction assay.


Subject(s)
Naphthoquinones/chemical synthesis , Serine Endopeptidases/metabolism , Serine Proteinase Inhibitors/chemical synthesis , Binding Sites , Cell Line , Cysteine/chemistry , Glutathione/chemistry , Humans , Leukocyte Elastase/metabolism , Molecular Structure , Naphthoquinones/pharmacology , Serine Proteinase Inhibitors/pharmacology , Thrombin/metabolism , Viral Plaque Assay
8.
Bioorg Med Chem ; 7(6): 1067-74, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10428375

ABSTRACT

In our search for new, safer anti-HCMV agents, we discovered that the natural product Arcyriaflavin A (la) was a potent inhibitor of HCMV replication in cell culture. A series of analogues (symmetrical indolocarbazoles) was synthesised to investigate structure activity relationships in this series against a range of herpes viruses (HCMV, VZV, HSV1, and 2). This identified a number of novel, selective and potent inhibitors of HCMV, 12,13-dihydro-2,10-difluoro-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazol e-5,7-(6H)-dione (1d) being the best example (IC50=40 nM, therapeutic index > 1450). Compounds described in this series were generally poor inhibitors of protein kinase C betaII, and no correlation was found between the ability to inhibit HCMV and the enzyme PKC.


Subject(s)
Antiviral Agents/chemical synthesis , Carbazoles/pharmacology , Cytomegalovirus/drug effects , Virus Replication/drug effects , Animals , Antiviral Agents/pharmacology , Carbazoles/chemistry , Cell Division/drug effects , Chlorocebus aethiops , Cytomegalovirus/physiology , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Herpesviridae/drug effects , Protein Kinase C/antagonists & inhibitors , Rats , Structure-Activity Relationship , Vero Cells
9.
Antivir Chem Chemother ; 9(3): 233-43, 1998 May.
Article in English | MEDLINE | ID: mdl-9875402

ABSTRACT

A number of symmetric and asymmetric 5'-phosphate esters of the potent anti-varicella-zoster virus (VZV) agent 1-(beta-D-arabinofuranosyl)-5-prop-1-ynyluracil (882C; netivudine) were prepared as potential lipophilic, membrane-soluble prodrugs of the bio-active phosphate forms. The compounds were prepared by the base-catalysed coupling of various phosphorochloridates with the free nucleoside analogue. Compounds were fully characterized by a range of spectroscopic and analytical methods and were studied for their inhibition of several viruses in tissue culture. All of the phosphate esters were inactive against human cytomegalovirus, herpes simplex virus type 2, VZV, human immunodeficiency virus type 1 and influenza A virus (EC50 > 100 microM) except the 5'-(4-nitrophenyl phenyl) phosphate, which inhibited influenza A virus. The relative rate of esterase-mediated hydrolysis of one of the lead target structures was measured in order to rationalize the poor antiviral action, and data were collected on possible metabolites in support of this analysis. Cell-specific esterases are implicated as key determinants of the antiviral potency of prodrugs of this type.


Subject(s)
Antiviral Agents/chemical synthesis , Arabinofuranosyluracil/analogs & derivatives , Prodrugs/chemical synthesis , Animals , Antiviral Agents/pharmacology , Antiviral Agents/toxicity , Arabinofuranosyluracil/chemical synthesis , Arabinofuranosyluracil/pharmacology , Cell Line , Esterases/metabolism , Liver/enzymology , Magnetic Resonance Spectroscopy , Mass Spectrometry , Molecular Structure , Phosphates/chemical synthesis , Phosphates/pharmacology , Phosphates/toxicity , Prodrugs/pharmacology , Swine
10.
Bioorg Med Chem Lett ; 8(19): 2623-8, 1998 Oct 06.
Article in English | MEDLINE | ID: mdl-9873592

ABSTRACT

A series of biaryl acids has been found to show micromolar inhibition of the HIV reverse transcriptase (RT) from types 1 and 2 with IC50S in the micromolar range. The series was discovered by consideration of the polymerase active site and sub-structure searching of the company compound collection. Synthesis of analogues to investigate the SAR is described. Two of these compounds have shown inhibition of HIV-2 RT only.


Subject(s)
Anti-HIV Agents/chemistry , Anti-HIV Agents/pharmacology , Carboxylic Acids/chemistry , Carboxylic Acids/pharmacology , HIV Reverse Transcriptase/antagonists & inhibitors , RNA-Directed DNA Polymerase/drug effects , Reverse Transcriptase Inhibitors/chemistry , Reverse Transcriptase Inhibitors/pharmacology , Anti-HIV Agents/chemical synthesis , Carboxylic Acids/chemical synthesis , Hydrocarbons, Aromatic/chemical synthesis , Hydrocarbons, Aromatic/chemistry , Hydrocarbons, Aromatic/pharmacology , Reverse Transcriptase Inhibitors/chemical synthesis , Structure-Activity Relationship
11.
J Chromatogr B Biomed Appl ; 677(1): 194-8, 1996 Feb 23.
Article in English | MEDLINE | ID: mdl-8925096

ABSTRACT

The binding properties of six indolocarbazole derivative have been measured using immobilised human serum albumin (HSA) in an HPLC column. The compounds showed very strong binding to HSA which necessitated the application of a 30 to 40% concentration of 2-propanol in the mobile phase. This represents a much higher concentration than is recommended by the column manufacturers. This HSA column had not changed its binding property when it was used again with 4% 2-propanol and 96% phosphate buffer. The binding parameters were estimated by extrapolation to 0% 2-propanol and were above 99% for each indolocarbazole derivative. The correlation analysis, including the calculated octanol/water partition coefficient (log P), pKa values as well as measured reversed-phase retention data of the compounds revealed that the extremely strong binding can be explained by the hydrophobic and acidic properties of the compounds.


Subject(s)
Antiviral Agents/pharmacokinetics , Carbazoles/pharmacokinetics , Indoles/pharmacokinetics , Antiviral Agents/analysis , Carbazoles/analysis , Chemical Phenomena , Chemistry, Physical , Chromatography, High Pressure Liquid , Humans , Indoles/analysis , Protein Binding , Serum Albumin , Solubility
12.
Nucleic Acids Symp Ser ; (16): 291-4, 1985.
Article in English | MEDLINE | ID: mdl-4088880

ABSTRACT

The reaction of various nucleophiles with 5-vinyl-2'-deoxyuridine has been studied in an attempt to explain the in vitro toxicity of the compound. Attempts to synthesise pro-drugs of 5-vinyl- and 5-ethynyl-2'-deoxyuridine are described.


Subject(s)
Deoxyuridine/analogs & derivatives , Deoxyuridine/chemical synthesis , Indicators and Reagents , Structure-Activity Relationship
SELECTION OF CITATIONS
SEARCH DETAIL
...