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1.
J Thromb Haemost ; 16(2): 389-404, 2018 02.
Article in English | MEDLINE | ID: mdl-29210180

ABSTRACT

Essentials Glycoprotein VI (GPVI) binds collagen, starting thrombogenesis, and fibrin, stabilizing thrombi. GPVI-dimers, not monomers, recognize immobilized fibrinogen and fibrin through their D-domains. Collagen, D-fragment and D-dimer may share a common or proximate binding site(s) on GPVI-dimer. GPVI-dimer-fibrin interaction supports spreading, activation and adhesion involving αIIbß3. SUMMARY: Background Platelet collagen receptor Glycoprotein VI (GPVI) binds collagen, initiating thrombogenesis, and stabilizes thrombi by binding fibrin. Objectives To determine if GPVI-dimer, GPVI-monomer, or both bind to fibrinogen substrates, and which region common to these substrates contains the interaction site. Methods Recombinant GPVI monomeric extracellular domain (GPVIex ) or dimeric Fc-fusion protein (GPVI-Fc2 ) binding to immobilized fibrinogen derivatives was measured by ELISA, including competition assays involving collagenous substrates and fibrinogen derivatives. Flow adhesion was performed with normal or Glanzmann thrombasthenic (GT) platelets over immobilized fibrinogen, with or without anti-GPVI-dimer or anti-αIIbß3. Results Under static conditions, GPVIex did not bind to any fibrinogen substrate. GPVI-Fc2 exhibited specific, saturable binding to both D-fragment and D-dimer, which was inhibited by mFab-F (anti-GPVI-dimer), but showed low binding to fibrinogen and fibrin under our conditions. GPVI-Fc2 binding to D-fragment or D-dimer was abrogated by collagen type III, Horm collagen or CRP-XL (crosslinked collagen-related peptide), suggesting proximity between the D-domain and collagen binding sites on GPVI-dimer. Under low shear, adhesion of normal platelets to D-fragment, D-dimer, fibrinogen and fibrin was inhibited by mFab-F (inhibitor of GPVI-dimer) and abolished by Eptifibatide (inhibitor of αIIbß3), suggesting that both receptors contribute to thrombus formation on these substrates, but αIIbß3 makes a greater contribution. Notably, thrombasthenic platelets showed limited adhesion to fibrinogen substrates under flow, which was further reduced by mFab-F, supporting some independent GPVI-dimer involvement in this interaction. Conclusion Only dimeric GPVI interacts with fibrinogen D-domain, at a site proximate to its collagen binding site, to support platelet adhesion/activation/aggregate formation on immobilized fibrinogen and polymerized fibrin.


Subject(s)
Blood Platelets/metabolism , Collagen/metabolism , Fibrin/metabolism , Fibrinogen/metabolism , Platelet Activation , Platelet Membrane Glycoproteins/metabolism , Thrombasthenia/blood , Thrombosis/blood , Binding Sites , Case-Control Studies , Fibrin/chemistry , Fibrin Fibrinogen Degradation Products/metabolism , Fibrinogen/chemistry , Humans , Platelet Adhesiveness , Platelet Glycoprotein GPIIb-IIIa Complex/genetics , Platelet Glycoprotein GPIIb-IIIa Complex/metabolism , Platelet Membrane Glycoproteins/chemistry , Platelet Membrane Glycoproteins/genetics , Protein Binding , Protein Interaction Domains and Motifs , Protein Multimerization , Signal Transduction , Structure-Activity Relationship , Thrombasthenia/genetics , Thrombosis/genetics
2.
Bone Joint J ; 98-B(12): 1662-1667, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27909129

ABSTRACT

AIMS: We present a case series of five patients who had revision surgery following magnetic controlled growing rods (MGCR) for early onset scoliosis. Metallosis was found during revision in four out of five patients and we postulated a mechanism for rod failure based on retrieval analysis. PATIENTS AND METHODS: Retrieval analysis was performed on the seven explanted rods. The mean duration of MCGR from implantation to revision was 35 months (17 to 46). The mean age at revision was 12 years (7 to 15; four boys, one girl). RESULTS: A total of six out of seven rods had tissue metallosis and pseudo-capsule surrounding the actuator. A total of four out of seven rods were pistoning. There were two rods which were broken. All rods had abrasive circumferential markings. A significant amount of metal debris was found when the actuators were carefully cut open. Analytical electron microscopy demonstrated metal fragments of predominantly titanium with a mean particle size of 3.36 microns (1.31 to 6.61). CONCLUSION: This study highlights concerns with tissue metallosis in MCGR. We recommend careful follow-up of patients who have received this implant. Cite this article: Bone Joint J 2016;98-B:1662-7.


Subject(s)
Bone Nails/adverse effects , Foreign Bodies/etiology , Scoliosis/surgery , Child , Child, Preschool , Device Removal , Female , Follow-Up Studies , Foreign Bodies/metabolism , Foreign Bodies/pathology , Humans , Magnetics , Male , Prosthesis Design , Prosthesis Failure , Reoperation/methods , Titanium/analysis
3.
J Thromb Haemost ; 13(12): 2253-9, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26447617

ABSTRACT

BACKGROUND: Atherothrombosis underlies acute coronary syndromes, including unstable angina and acute myocardial infarction. Within the unstable plaque, monocytes express collagenolytic matrix metalloproteinases (MMPs), including MMP-13, which degrades fibrous collagen. Following rupture, vessel wall components including degraded collagen are exposed to circulating platelets. Platelet receptors then mediate the recruitment and activation of platelets to form a thrombus, blocking blood flow and resulting in myocardial infarction and sudden death. OBJECTIVES: Here we aim to provide information on the effects of collagen degradation on platelet adhesion and thrombus formation. METHODS: Using increasing concentrations of MMP-13, we induced progressive degradation of fibrous and monomeric collagen I, visualized by electrophoresis, and then investigated the capacity of the resulting fragments to support static platelet adhesion and thrombus formation in whole flowing blood. RESULTS: Both integrin and glycoprotein VI-dependent interactions with fibrous collagen underpin high levels of platelet adhesion under both conditions, with little obvious effect of MMP-13 treatment. Static platelet adhesion to monomeric collagen was strongly α2ß1-dependent regardless of degradation status. Under flow conditions, partially degraded monomeric collagen supported increased thrombus deposition at 10 µg mL(-1) MMP-13, falling close to background when collagen degradation was complete (100 µg mL(-1) MMP-13). CONCLUSIONS: New binding activities come into play after partial digestion of collagen monomers, and net platelet-reactivity through all axes is abolished as degradation becomes more complete.


Subject(s)
Blood Platelets/metabolism , Collagen Type I/metabolism , Matrix Metalloproteinase 13/metabolism , Platelet Adhesiveness , Thrombosis/metabolism , Electrophoresis, Polyacrylamide Gel , Humans , Integrin alpha2beta1/metabolism , Proteolysis , Thrombosis/blood , Thrombosis/enzymology
4.
Eur Spine J ; 23 Suppl 1: S61-5, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24413746

ABSTRACT

PURPOSE: Magnetically controlled growing rod systems have been introduced over recent years as an alternative to traditional growing rods for management of early onset scoliosis. The purpose of this paper is to report our early experience of a magnetically controlled growing rod system (MAGEC, Ellipse). METHODS: Review of pre-operative, postoperative and follow-up Cobb angles and spinal growth in case series of eight patients with a minimum 23 months' follow-up (23-36 months). RESULTS: A total of six patients had dual rod constructs implanted and two patients received single-rod constructs. Four patients had MAGEC rods as a primary procedure. Four were revisions from other systems. Mean age at surgery in the primary group was 4.5 years (range 3.9-6.9). In patients who had MAGEC as a primary procedure, mean pre-operative Cobb angle was 74° (63-94), with postoperative Cobb angle of 42° (32-56) p ≤ 0.001 (43% correction). Mean Cobb angle at follow-up was 42° (35-50). Spinal growth rate was 6 mm/year. One sustained proximal screw pull out. A final patient sustained a rod fracture. Mean age at surgery in the revision group was 10.9 years (range 9-12.6). Mean pre-operative Cobb angle was 45° (34-69). Postoperative Cobb angle was 42° (33-63) (2% correction). Mean Cobb angle at follow-up was 44° (28-67). Mean spinal growth rate was 12 mm/year. Two patients developed loss of distraction. CONCLUSION: MAGEC growing rod system effectively controls early onset scoliosis when used as either a primary or revision procedure. Although implant-related complications are not uncommon, the avoidance of multiple surgeries following implantation is beneficial compared with traditional growing rod systems.


Subject(s)
Internal Fixators , Magnets , Orthopedic Procedures/instrumentation , Scoliosis/surgery , Child , Child, Preschool , Female , Follow-Up Studies , Humans , Male , Orthopedic Procedures/methods , Postoperative Complications , Treatment Outcome
5.
Pharmazie ; 67(5): 406-10, 2012 May.
Article in English | MEDLINE | ID: mdl-22764572

ABSTRACT

The effect of delta1-cortienic acid (delta1-CA) on human skin blanching activity of the soft corticosteroid, loteprednol etabonate (LE), has been studied. Ten volunteers had applied to their forearms a dose of LE ranging from 0.1 to 1 mM, or LE from 0.1 to 1 mM in combination with 2-times the concentration of delta1-CA (0.2 - 2mM). The results indicate that delta1-CA increased LE's effect on human vasoconstriction/skin blanching activity, both in the intensity and duration. This enhancing effect of delta1-CA was also observed in other blanching studies with other corticosteroids, such as hydrocortisone. The enhancement may occur through the displacement of LE bound to transcortin (also known as corticosteroid-binding globulin, or CBG) by delta1-CA as delta1-CA has a higher affinity for CBG than that for glucocorticoid receptor (GR), resulting in more free-LE to act on GR, and increased skin blanching. In rat studies, intravenous injection of delta1-CA (5-50 mg/kg) did not affect the pharmacokinetics of LE (5 mg/kg), indicating that delta1-CA is safe for combined use with LE. In stability studies, the presence of delta1-CA at the same concentrations as LE in aqueous suspension (0.1 and 0.2%) significantly increased the stability of LE. Thus, the combination of delta1-CA with LE serves an enhancing and stabilizing role while not impacting the pharmacokinetic properties of LE.


Subject(s)
Androstadienes/chemistry , Androstadienes/pharmacology , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Skin/blood supply , Adolescent , Adult , Androstadienes/pharmacokinetics , Animals , Anti-Inflammatory Agents/pharmacokinetics , Biotransformation , Chromatography, High Pressure Liquid , Drug Stability , Forearm/blood supply , Humans , Hydrocortisone/pharmacology , Indicators and Reagents , Injections, Intravenous , Loteprednol Etabonate , Middle Aged , Rats , Rats, Sprague-Dawley , Regional Blood Flow/drug effects , Spectrophotometry, Ultraviolet , Suspensions , Vasoconstriction/drug effects , Young Adult
6.
J Bone Joint Surg Br ; 90(5): 619-21, 2008 May.
Article in English | MEDLINE | ID: mdl-18450629

ABSTRACT

We have examined the outcome in 19 professional rugby union players who underwent anterior cervical discectomy and fusion between 1998 and 2003. Through a retrospective review of the medical records and telephone interviews of all 19 players, we have attempted to determine the likelihood of improvement, return to professional sport and the long-term consequences. We have also attempted to relate the probability of symptoms in the neck and radicular pain in the arm to the position of play. Neck and radicular pain were improved in 17 patients, with 13 returning to rugby, the majority by six months after operation. Of these, 13 returned to their pre-operative standard of play, one to a lower level and five have not played rugby again. Two of those who returned to the game have subsequently suffered further symptoms in the neck, one of whom was obliged to retire. The majority of the players with problems in the neck were front row forwards. A return to playing rugby union after surgery and fusion of the anterior cervical spine is both likely and safe and need not end a career in the game.


Subject(s)
Cervical Vertebrae/surgery , Diskectomy , Football/injuries , Intervertebral Disc Displacement/surgery , Neck Pain/surgery , Recovery of Function , Adult , Cervical Vertebrae/injuries , Diskectomy/methods , Diskectomy/rehabilitation , Humans , Injury Severity Score , Intervertebral Disc Displacement/rehabilitation , Male , Neck Pain/physiopathology , Retrospective Studies , Risk Factors , Spondylolysis/surgery , Time Factors , Treatment Outcome
7.
Int J Neurosci ; 117(11): 1579-90, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17917927

ABSTRACT

Two questions regarding findings from the Women's Health Initiative are (1) What is the effect of various hormonal regimens including selective estrogen receptor modulators? and (2) Is the negative effect on cognitive functioning related to the older age (65+ years) of the women? This study addresses these two questions in a short-term randomized trial of the effects of raloxifene versus alendronate on cognition. The study found only one significant interaction where the raloxifene and alendronate group changed differently across the two testing occasions. Hence, raloxifene does not have any impact, positive or negative, on short-term cognitive functioning when compared to alendronate.


Subject(s)
Bone Density Conservation Agents/adverse effects , Cognition/drug effects , Raloxifene Hydrochloride/adverse effects , Aged , Alendronate/adverse effects , Alendronate/therapeutic use , Bone Density Conservation Agents/therapeutic use , Educational Status , Female , Humans , Middle Aged , Neuropsychological Tests , Osteoporosis/drug therapy , Postmenopause , Raloxifene Hydrochloride/therapeutic use
8.
Toxicon ; 49(5): 734-9, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17196631

ABSTRACT

Envenoming by the West African saw-scaled viper, Echis ocellatus resembles that of most vipers, in that it results in local blistering, necrosis and sometimes life-threatening systemic haemorrhage. While effective against systemic envenoming, current antivenoms have little or no effect against local tissue damage. The major mediators of local venom pathology are the zinc-dependant snake venom metalloproteinases (SVMPs). The high degree of structural and functional homology between SVMPs and their mammalian relatives the matrix metalloproteinases (MMPs) suggests that substrate/inhibitor interactions between these subfamilies are likely to be analogous. In this study, four recently developed MMP inhibitors (MMPIs) (Marimastat, AG-3340, CGS-270 23A and Bay-12 9566) are evaluated in addition to three metal ion chelators (EDTA, TPEN and BAPTA) for their ability to inhibit the haemorrhagic activities of the medically important E. ocellatus venom and one of its haemorrhagic SVMPs, EoVMP2. As expected, the metal ion chelators significantly inhibited the haemorrhagic activities of both whole E. ocellatus venom and EoVMP2, while the synthetic MMPIs show more variation in their efficacies. These variations suggest that individual MMPIs show specificity towards SVMPs and that their application to the neutralization of local haemorrhage may require a synthetic MMPI mixture, ensuring that a close structural component for each SVMP is represented.


Subject(s)
Chelating Agents/therapeutic use , Hemorrhage/prevention & control , Metalloproteases/antagonists & inhibitors , Protein Kinase Inhibitors/therapeutic use , Snake Bites/drug therapy , Viper Venoms/antagonists & inhibitors , Animals , Biphenyl Compounds , Chelating Agents/pharmacology , Chromatography, Gel , Chromatography, Liquid , Edetic Acid/pharmacology , Edetic Acid/therapeutic use , Egtazic Acid/analogs & derivatives , Egtazic Acid/pharmacology , Egtazic Acid/therapeutic use , Ethylenediamines/pharmacology , Ethylenediamines/therapeutic use , Evaluation Studies as Topic , Hemorrhage/etiology , Hydroxamic Acids/pharmacology , Hydroxamic Acids/therapeutic use , Metalloproteases/toxicity , Mice , Molecular Structure , Organic Chemicals/pharmacology , Organic Chemicals/therapeutic use , Phenylbutyrates , Protein Kinase Inhibitors/pharmacology , Pyrazines/pharmacology , Pyrazines/therapeutic use , Snake Bites/complications , Statistics, Nonparametric , Sulfonamides/pharmacology , Sulfonamides/therapeutic use , Viper Venoms/toxicity
9.
Pharmazie ; 61(2): 125-34, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16526560

ABSTRACT

Talampanel is a 2,3-benzodiazepine-type allosteric (noncompetitive) AMPA-antagonist currently being developed as an orally active, broad-spectrum anticonvulsant. Here, a detailed study of its N-acetylation in humans is presented using plasma concentration data of both TLP and its N-acetyl metabolite obtained from healthy volunteers (n = 28) genotyped for N-acetyltansferase NAT2 isozymes. Plasma samples were obtained for up to 48 h after a single oral dose of 75 mg TLP both in fasted and in fed subjects. A perfect correspondence could be established between the phenotype inferred before the study from genotyping and that determined after the study by using plasma metabolite-to-parent molar ratios confirming that this route of metabolism is indeed mediated by NAT2. Analysis of the data has been performed using both noncompartmental analysis and a custom-built, unified parent-metabolite PK model, which incorporates three different acetylation rates according to the genotype-based classification of each subject as slow, intermediate, or fast acetylator to simultaneously fit plasma levels for both TLP and its metabolite. This suggest that for TLP in humans, (i) N-acetylation represents only a relatively small fraction of its total elimination (about one-fourth in fast acetylators and much less in slow acetylators), (ii) acetylation is about eight-twelve times faster in fast and three-six times faster in intermediate acetylators than in slow acetylators, and (iii) the N-acetyl metabolite is eliminated faster than the parent TLP.


Subject(s)
Arylamine N-Acetyltransferase/genetics , Benzodiazepines/metabolism , Excitatory Amino Acid Antagonists/metabolism , Polymorphism, Genetic/genetics , Acetylation , Adolescent , Adult , Algorithms , Area Under Curve , Benzodiazepines/pharmacokinetics , Cross-Over Studies , DNA/genetics , Double-Blind Method , Eating/physiology , Ethnicity , Excitatory Amino Acid Antagonists/pharmacokinetics , Fasting/physiology , Genotype , Humans , Male , Phenotype
10.
Int J Parasitol ; 36(4): 453-66, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16500655

ABSTRACT

Commonly studied nematode parasites have not proven amenable to simple genetic analyses and this has significantly reduced the available research options. We introduce here a nematode parasite of mammals, Parastrongyloides trichosuri, which has features uniquely suited for genetic analysis. This parasite has the capacity to undergo multiple reproductive cycles as a free-living worm and thereby amplify the numbers of its infective L3s in faeces. Culture conditions are presented that permit facile laboratory maintenance of this worm for >90 free-living life cycles (to date) without the need for re-entry into a permissive host. Even after long maintenance as a free-living worm, culture conditions can be manipulated to favour development of infective L3 worms, which remain able to successfully infect their marsupial hosts. The switch to infective L3 development is triggered by a secreted factor contained in culture medium conditioned by multiple generations of free-living worm culture. It is simple to perform single pair crosses with P. trichosuri to carry out Mendelian genetics in the laboratory and this has been done multiple times with sibling pairs to generate highly inbred lines. Lines of worms can readily be cryopreserved and recovered. Over 7000 expressed sequence tags have been produced from cDNAs at different life cycle stages and used to identify single nucleotide polymorphisms and microsatellites as genetic markers. Free-living worms live only a few days on average while the patency of parasitic infections can last for several months. Since we show this is not the result of re-infection, we conclude that parasitic worms have a lifespan capacity at least 20-30 times longer than their free-living counterparts. We discuss how it should be possible to exploit these unique features of P. trichosuri as a model for future studies that explore the genetic basis of longevity and parasitism.


Subject(s)
Strongyloides/genetics , Strongyloidiasis/parasitology , Animals , Culture Media, Conditioned , Feces/parasitology , Female , Fertility , Genetic Markers , Host-Parasite Interactions , Life Cycle Stages , Longevity , Male , Models, Biological , Parasite Egg Count , Strongyloides/growth & development , Strongyloides/pathogenicity , Strongyloides/physiology , Temperature , Trichosurus/parasitology
11.
Int J Parasitol ; 36(4): 467-74, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16469320

ABSTRACT

Parastrongyloides trichosuri is a nematode parasite of Australian brushtail possums that has an alternative free-living life cycle which can be readily maintained indefinitely in a laboratory setting. The ability to maintain this parasite in a free-living cycle and induce it to parasitism at the free-living L1 stage makes this an excellent model for the study of genes associated with parasitism. A 70kD protein from infective larvae of P. trichosuri that appears to be immunogenic in infected possums has been identified as a heat shock protein (Hsp)70 homologue. The complete gene for Pt-Hsp70 was cloned and sequenced. The protein encoded by the Pt-Hsp70 gene is the likely orthologue of the Caenorhabditis elegans protein, Hsp70A, also known as hsp-1. Reverse transcriptase-PCR data indicate that Pt-Hsp70 (designated Pt-hsp-1) is expressed at readily detectable levels in all developmental stages of both the parasitic and free-living P. trichosuri life cycles and the promoter is mildly inducible by heat shock. Bioinformatic analysis of expressed sequence tag databases indicates that C. eleganshsp-1 homologues, together with C. eleganshsp-3 homologues, are the predominant members of the Hsp70 superfamily that are normally expressed in parasitic stages of the Strongyloididae family. Promoter fusions to a beta-galactosidase coding sequence were prepared and introduced into wild type C. elegans to produce transgenic nematodes. Reporter gene expression was clearly present within embryonic cells and within intestinal cells of larval and adult stages. Thus, the expression of the Pt-hsp-1 promoter within P. trichosuri and transgenic C. elegans appears similar to the known expression of C. elegans hsp-1. This promoter should be of value in efforts to develop genetic manipulation tools for P. trichosuri.


Subject(s)
Genes, Helminth , HSP70 Heat-Shock Proteins/genetics , Helminth Proteins/genetics , Strongyloides/genetics , Amino Acid Sequence , Animals , Base Sequence , Caenorhabditis elegans Proteins/genetics , Computational Biology , Gene Expression Regulation, Developmental , HSP70 Heat-Shock Proteins/isolation & purification , Helminth Proteins/isolation & purification , Molecular Sequence Data , Promoter Regions, Genetic , Reverse Transcriptase Polymerase Chain Reaction/methods , Strongyloides/growth & development , Strongyloides/metabolism , Strongyloidiasis/parasitology , Transformation, Genetic , Trichosurus/parasitology
12.
Biochim Biophys Acta ; 1724(1-2): 194-202, 2005 Jun 20.
Article in English | MEDLINE | ID: mdl-15863354

ABSTRACT

Two metalloproteinases, a 24-kDa P-I EoVMP1 and a 56-kDa P-III EoVMP2, have recently been isolated from the venom of the West African saw-scaled viper Echis ocellatus. We now reveal a new 65-kDa haemorrhagic group P-III metalloproteinase which we have designated EoVMP3. The aim of this study was to determine whether these three snake venom metalloproteinases (SVMPs) affect platelets and blood coagulation. EoVMP1 had no effect on the aggregation of washed human platelets, whereas EoVMP2 inhibited collagen-induced platelet aggregation. In contrast, EoVMP3 did not inhibit the aggregation of platelets by collagen but instead activated platelets in the absence of any additional co-factors. All three SVMPs were capable of activating prothrombin to varying degrees and can therefore be described as procoagulants. EoVMP1, EoVMP2 and EoVMP3 share sequence identity with other members of the reprolysin family, but differ greatly in their effects on some of the components that control haemostasis.


Subject(s)
Blood Coagulation/drug effects , Metalloproteases/pharmacology , Platelet Aggregation/drug effects , Viper Venoms/enzymology , Amino Acid Sequence , Animals , Fibrinogen/antagonists & inhibitors , Fibrinogen/chemistry , Molecular Sequence Data , Prothrombin/antagonists & inhibitors , Prothrombin/chemistry , Viper Venoms/isolation & purification , Viperidae/metabolism
13.
Diabetes Obes Metab ; 7(3): 273-81, 2005 May.
Article in English | MEDLINE | ID: mdl-15811145

ABSTRACT

OBJECTIVE: The objective of the study was to investigate the effects of cerivastatin therapy on forearm endothelial dependent acetylcholine (ACH) and independent (nitroprusside) vasodilator responses, blood pressure (BP) responses to intravenous infusions of angiotensin II (AII) and noradrenaline (NA) and on 24-h ambulatory BP recordings in type 2 diabetic men. DESIGN: Eleven type 2 diabetic men aged 59 +/- 9 years with total cholesterol levels of 5.0 +/- 1.26 mmol/l, triglycerides of 2.23 mmol/l and high-density lipoprotein cholesterol levels of 1.24 mmol/l completed a double-blind, randomized, crossover trial comparing 8 weeks of cerivastatin therapy (800 microg of nocte) with placebo. Forearm vascular resistance (FVR) responses to intrabrachial-arterial infusions of ACH (3-24 microg/min), nitroprusside (2-16 microg/min), the nitric oxide(NO) synthase inhibitor l-nitro-mono-methyl arginine (l-nmma) (8 micromol/min), ACH during l-NMMA infusion and BP responses to intravenous infusions of AII (12.5-50 ng/min) and NA (20-400 ng/min) were measured at the end of each treatment period. Twenty-four-hour ambulatory BP recordings were also performed. RESULTS: FVR responses to ACH during l-NMMA infusion were significantly (p = 0.026) greater during cerivastatin than during placebo therapy. In contrast, FVR responses to ACH in the absence of NO synthase inhibition did not differ significantly between cerivastatin and placebo therapies (p = 0.81). FVR increased by 31.4 +/- 57.3% in response to l-NMMA infusion during cerivastatin therapy compared with 6.1 +/- 41.2% during placebo therapy (p = 0.20). FVR responses to nitroprusside did not differ between cerivastatin and placebo therapies (p = 0.28), nor did BP responses to AII (systolic BP, p = 0.99; diastolic BP, p = 0.98) or NA (systolic BP, p = 0.21; diastolic BP, p = 0.48). Mean 24-h BP was similar during cerivastatin (123 +/- 10 or 70 +/- 7 mmHg) and placebo therapies (129 +/- 11 or 74 +/- 7 mmHg) (systolic BP, p = 0.26; diastolic BP, p = 0.41). CONCLUSION: Cerivastatin increases FVR responses to ACH in type 2 diabetic men with mild dyslipidaemia but only following NO synthase inhibition. This may indicate an improvement in endothelium-derived hyperpolarizing factor-mediated responses.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Pyridines/therapeutic use , Vascular Resistance/drug effects , Acetylcholine , Aged , Analysis of Variance , Angiotensin II , Blood Pressure Monitoring, Ambulatory , Cross-Over Studies , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/physiopathology , Double-Blind Method , Endothelium, Vascular/drug effects , Forearm/blood supply , Humans , Hyperlipidemias/complications , Hyperlipidemias/drug therapy , Hypertension/complications , Hypertension/drug therapy , Infusions, Intravenous , Male , Middle Aged , Nitric Oxide Synthase/antagonists & inhibitors , Nitroprusside/therapeutic use , Norepinephrine , Vasodilator Agents , omega-N-Methylarginine
14.
Toxicon ; 45(5): 677-80, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15777964

ABSTRACT

The antigenic relationship between snake venom metalloproteinases (SVMPs) was analysed using rabbit antisera raised against the native forms of two SVMPs purified from Echis ocellatus venom. Using enzyme-linked immunosorbent assay (ELISA), western blotting and two-dimensional SDS-PAGE, our findings show that antibodies raised against EoVMP1, a non-haemorrhagic class P-I 24kDa SVMP, and EoVMP2, a haemorrhagic class P-III 56kDa SVMP, demonstrate cross-reactivities which relate to the domain hierarchy observed in class P-I to P-III/IV SVMPs. A third 65kDa P-III metalloproteinase (designated EoVMP3) was also isolated from E. ocellatus venom using hydrophobic interaction, size exclusion and anion exchange chromatography. In comparative immunoassays, EoVMP2 and EoVMP3 bound strongly to the commercial monovalent ovine Fab fragment antivenom EchiTAbtrade mark (raised against the same venom), but EoVMP1 showed no cross-reactivity. This could indicate that antivenoms may lack antibodies to potentially important venom components.


Subject(s)
Antibodies/immunology , Immune Sera/immunology , Metalloproteases/immunology , Viper Venoms/enzymology , Viperidae , Animals , Blotting, Western , Chromatography, Gel , Chromatography, Ion Exchange , Cross Reactions/immunology , Electrophoresis, Polyacrylamide Gel , Enzyme-Linked Immunosorbent Assay , Immunoassay , Rabbits
15.
Climacteric ; 7(1): 70-7, 2004 Mar.
Article in English | MEDLINE | ID: mdl-15259285

ABSTRACT

OBJECTIVE: To examine the effects of dietary isoflavone supplementation with an extract from red clover on cognitive function in postmenopausal women. DESIGN: Thirty postmenopausal women aged greater than 60 years received either two tablets of an extract of aglycone isoflavones from red clover (each containing formononetin 25 mg, biochanin 2.5 mg and less than 1 mg of daidzein and genistein) for 6 months in a randomized, controlled clinical trial. Cognitive function tests were performed at baseline and at the end of isoflavone or placebo therapy. RESULTS: Isoflavone supplementation was associated with an apparent improvement in block design (a test of visual-spatial intelligence) compared to placebo (isoflavone +12%, placebo -3%; p = 0.03), no improvement in verbal memory compared to an improvement on placebo (isoflavone +1%, placebo +29%; p = 0.023) and a deterioration in digit recall compared to placebo (isoflavone -6%, placebo +12%; p = 0.029). However, these findings were not statistically significant when corrections were made for potential chance findings due to multiple comparisons. CONCLUSION: Isoflavone supplementation does not appear to have major short-term effects on cognitive function in postmenopausal women. However, further clinical trials are required to determine whether small effects or long-term effects on cognitive function occur during isoflavone supplementation.


Subject(s)
Cognition/drug effects , Dietary Supplements , Isoflavones/therapeutic use , Phytotherapy , Postmenopause/physiology , Trifolium , Cognition/physiology , Enzyme Inhibitors/therapeutic use , Estrogens, Non-Steroidal/therapeutic use , Female , Genistein/therapeutic use , Humans , Mental Recall/drug effects , Mental Recall/physiology , Middle Aged , Neuropsychological Tests , Plant Preparations/therapeutic use , Verbal Learning/drug effects , Verbal Learning/physiology
17.
Diabetes Obes Metab ; 5(5): 325-32, 2003 Sep.
Article in English | MEDLINE | ID: mdl-12940870

ABSTRACT

OBJECTIVE: The aim of this study was to determine whether dietary supplementation with isoflavones from red clover affected ambulatory blood pressure and forearm vascular endothelial function in postmenopausal type 2 diabetic women. DESIGN: Sixteen postmenopausal type 2 diabetics treated with diet or oral hypoglycaemic therapy completed a randomized double-blind crossover trial of dietary supplementation with isoflavones from red clover (approximately 50 mg/day) for 4 weeks compared to placebo. Twenty-four-hour ambulatory blood pressure recordings and forearm vascular responses to acetylcholine, nitroprusside and L-nitromonomethylarginine (L-NMMA) were measured at the end of each treatment period. RESULTS: Mean daytime systolic and diastolic blood pressures were significantly lower during isoflavone therapy compared to placebo (-8.0 +/- 3.4 and -4.3 +/- 1.9 mmHg respectively, p < 0.05). The increase in forearm vascular resistance following L-NMMA was significantly greater during isoflavone supplementation (20.9 +/- 6.5) than placebo (3.7 +/- 2.9 arbitrary units, p < 0.05), suggesting an improvement in basal endothelial function. Plasma lipoproteins, glycated haemoglobin and forearm vascular responses to acetylcholine and nitroprusside did not differ significantly between isoflavone and placebo therapy. CONCLUSION: Isoflavone supplementation from red clover may favourably influence blood pressure and endothelial function in postmenopausal type 2 diabetic women.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Isoflavones/therapeutic use , Phytotherapy/methods , Plant Extracts/therapeutic use , Trifolium , Aged , Blood Pressure/drug effects , Blood Pressure Monitoring, Ambulatory , Cross-Over Studies , Diabetes Mellitus, Type 2/physiopathology , Double-Blind Method , Endothelium, Vascular/drug effects , Endothelium, Vascular/physiopathology , Female , Forearm/blood supply , Humans , Middle Aged , Postmenopause , Vascular Resistance/drug effects
18.
Toxicon ; 42(1): 21-7, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12893057

ABSTRACT

Separation of previously uncharacterised Echis ocellatus venom by phenyl-Superose FPLC (Fast Liquid Protein Chromatography) yielded eight protein fractions. Three of these displayed high proteolytic activity when assayed by in vivo and in vitro assays (including enzyme linked immunosorbant assay), and were further separated using Superdex 75 and Mono-Q FPLC. This resulted in the purification of a non-haemorrhagic 24 kDa metalloproteinase (EoVMP1, pI 7.0), and a haemorrhagic 56 kDa metalloproteinase (EoVMP2, pI 5.5). Following tryptic digest, short amino acid sequences of EoVMP1 and EoVMP2 were obtained using Edman degradation. Both sequences displayed homology when aligned with existing snake venom metalloproteinases (SVMPs). The strong homology observed among previously well-characterised SVMPs suggests that principles governing the interaction of substrates and inhibitors are likely to be similar for EoVMP1, EoVMP2 and all members of the reprolysin family.


Subject(s)
Metalloendopeptidases/isolation & purification , Viper Venoms/chemistry , Viperidae , Amino Acid Sequence , Animals , Chromatography, Liquid , Collagen Type IV/drug effects , Collagen Type IV/metabolism , Enzyme-Linked Immunosorbent Assay , Hemorrhage/chemically induced , Hemorrhage/pathology , Male , Metalloendopeptidases/pharmacology , Mice , Mice, Inbred Strains , Molecular Sequence Data , Sequence Alignment
19.
Pharmazie ; 57(2): 142-6, 2002 Feb.
Article in English | MEDLINE | ID: mdl-11878192

ABSTRACT

The aim of the present study was to evaluate the soft corticosteroid BNP-166 in rats and dogs treated orally with 0.2, 2.0, and 20.0 mg/kg for 28 days and the reversibility of any abnormalities during a 14-day post-dosing period. The test substance, BNP-166, was well tolerated during the 28-day treatment period. The observed changes were all characteristic for the pharmacological actions of a glucocorticoid. Treatment related changes occurred in the adrenals and thymus, and, to a lesser extent, in the lymph nodes, spleen and liver. There were no statistically significant reductions in the cortisol levels of all groups in the 0.2 and 2 mg/kg treatments. Significant reductions were observed in the high-dose group (20 mg/kg), but levels returned to normal by the end of the 14-day recovery period. Based on the results, the No Observable Adverse Effect Level (NOAEL) of BNP-166 soft corticosteroid in rat and dog after 28-day oral administration is 2 mg/kg. This value is approximately 40 times higher than that of budesonide. Pharmacodynamic and receptor binding studies have shown BNP-166 to have a similar potency to budesonide; therefore, BNP-166 can be considered safer when administered orally than other corticosteroids such as prednisolone or budesonide.


Subject(s)
Adrenal Cortex Hormones/toxicity , Adrenal Glands/pathology , Animals , Body Weight/drug effects , Dogs , Female , Lymph Nodes/pathology , Male , Rats , Species Specificity , Thymus Gland/pathology
20.
Climacteric ; 4(1): 13-8, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11379373

ABSTRACT

OBJECTIVES: To assess the acceptability of the delivery of an isoflavone supplementation in the form of a powdered drink, and whether the supplementation of dietary isoflavones in this manner decreased the incidence of menopausal flushes. The secondary aims included assessment of other symptoms or parameters of estrogen deficiency and responses to isoflavones. METHODS: A randomized, double-blind, placebo-controlled, parallel-group trial comprising 24 postmenopausal women with symptoms of estrogen deficiency was performed over a 12-week period. The women were randomized to receive a dietary beverage containing isoflavones or an isoflavone-free, isocaloric placebo preparation. RESULTS: Although there was a high compliance rate among individual patients, there was a 25% withdrawal rate from the study in the active group. The incidence of complaints of bad taste tended to be higher in the active group (p = 0.07), and the total number of adverse events was significantly higher in this group (p < 0.001). There was no statistically significant difference in the incidence of flushes between the groups. There was no difference between the groups in Greene Menopause Symptom Scores, vaginal maturation value, levels of follicle stimulating hormone (FSH) or sex hormone-binding globulin (SHBG), or bone turnover markers. CONCLUSIONS: Powdered energy drinks are not commonly consumed in Australia and were poorly tolerated in this study. The high withdrawal rate and reporting of side-effects suggests that other methods of isoflavone delivery may be more appropriate in this culture, in future trials. At the dose used no benefit was seen in relief from menopausal symptoms, although for the sample size, the study could only have been expected to detect major differences between the groups.


Subject(s)
Beverages , Food, Formulated , Glycine max , Hot Flashes/drug therapy , Hot Flashes/psychology , Isoflavones/therapeutic use , Menopause/drug effects , Menopause/psychology , Patient Acceptance of Health Care/psychology , Beverages/analysis , Double-Blind Method , Female , Follicle Stimulating Hormone/blood , Food, Formulated/adverse effects , Food, Formulated/analysis , Hot Flashes/blood , Hot Flashes/classification , Hot Flashes/physiopathology , Humans , Isoflavones/adverse effects , Menopause/physiology , Middle Aged , Powders , Severity of Illness Index , Sex Hormone-Binding Globulin/metabolism , Glycine max/chemistry
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