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C Bourne

Publications and source records attributed to C Bourne.

11 recordsLinked to original sources
PubMed2001

Use of a polymerase chain reaction assay to detect infection with Eperythrozoon wenyoni in cattle.

OBJECTIVE: To determine whether a polymerase chain reaction (PCR) assay could be used to detect Eperythrozoon wenyoni in the blood of cattle. DESIGN: Prospective study. ANIMALS: 95 cattle from various herds in Alabama and Georgia and 96 bulls enrolled in Auburn University's Alabama Beef Cattle Improvement Association Bull Test program. PROCEDURE: Blood samples were collected by means of venipuncture of the median caudal vein and submitted for a CBC and PCR assay. Blood smears were made immediately after blood collection and examined by means of light microscopy. RESULTS: Three of 95 cattle from herds in Alabama and Georgia and 5 of 96 bulls enrolled in the Bull Test program had positive PCR assay results. Organisms were seen in blood smears from only 5 of these 8 animals. Organisms were not seen in blood smears from any animals for which results of the PCR assay were negative. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a PCR assay may be an effective method for detecting E wenyoni infection in cattle and that the PCR assay may be a more sensitive test than evaluation of blood smears.

Alabama↗
PubMed2001

Nucleotide sequence of the canine alphaIIb gene from platelet-derived cDNA.

OBJECTIVE: To determine the nucleotide sequence of the alphaIIb gene from canine platelet-derived cDNA. ANIMALS: 3 adult dogs. PROCEDURE: First-strand cDNA was prepared from total RNA isolated from canine platelets. The cDNA was amplified, using specific primers in polymerase chain reaction (PCR), and the nucleotide sequence was obtained from purified PCR products. RESULTS: Except for the nucleotide at position 694, results of all sequencing reactions of alphaIIb were identical for canine platelet-derived cDNA. Canine alphaIIb had 3 fewer codons than alphaIIb of humans. The nucleotide and deduced amino acid sequences of full-length canine alphaIIb shared > or = 83% similarity with the sequences established for humans. Segments of canine alphaIIb nucleotide and deduced amino acid sequences were > or = 78% similar to alphaIIb associated with 7 functional domains (extracellular, transmembrane, cytoplasmic, and 4 calcium-binding domains) in humans, with the highest degree of similarity correlating with the sequences of the 4 calcium-binding domains. Amino acid residues associated with development of alloantibodies in humans (Met837, Val837, Ile843, Ser843) are not encoded by canine alphaIIb. CONCLUSIONS AND CLINICAL RELEVANCE: The nucleotide variation at position 694 of canine alphaIIb may represent a polymorphism. The species differences in the alphaIIb sequence may contribute to variations in receptor-li gand interactions. The high degree of alphaIIb sequence conservation of the 4 calcium-binding domains implies functional importance. Some disorders associated with alphaIIbbeta3 in dogs are clinically analogous to diseases in humans, and results indicate that dogs are an appropriate model for the evaluation of gene therapy and other treatments of platelet-associated disorders.

Amino Acid Sequence↗
PubMed2000

Two genetic defects in alphaIIb are associated with type I Glanzmann's thrombasthenia in a Great Pyrenees dog: a 14-base insertion in exon 13 and a splicing defect of intron 13.

Glannzmann's thrombasthenia (GT) is an autosomal recessive bleeding disorder caused by qualitative or quantitative deficiencies of the platelet membrane glycoprotein alphaIIbbeta3. This is the first report of a molecular genetic basis for type I GT in dogs. As previously reported, a thrombasthenic Great Pyrenees dog (dog No. 1) experienced uncontrolled epistaxis despite results of coagulation screening tests, platelet quantitation, and von Willebrand factor quantitation that were within reference ranges. Platelet aggregation was minimal in response to agonists. Flow cytometry, autoradiography, and immunoblot experiments demonstrated either marked reduction or absence of glycoproteins alphaIIb and beta3. In this study, we report the presence of a 14-base insertion in exon 13 and defective splicing of intron 13 in the alphaIIb gene of two thrombasthenic dogs (Nos. 1 and 8). The insertion disrupted the fourth alphaIIb calcium-binding domain, caused a shift in the reading frame and resulted in a premature termination codon. Possible consequences of this mutation include decreased alphaIIb mRNA stability and production of truncated alphaIIb protein that lacks the transmembrane and cytoplasmic domains and a large portion of the extracellular domain. We identified the dam, sire, and three littermates of dog No. 8 as carriers of the alphaIIb mutation. Canine alphaIIb and beta3 genes share significant homology with the genes in human beings, making canine GT an excellent translational model for human GT. A defined molecular basis for canine GT will enhance ongoing gene therapy research and increase the understanding of structure-function relationships of this integrin.

Alternative Splicing↗
PubMed1999

DNA sequence of the canine platelet beta3 gene from cDNA: comparison of canine and mouse beta3 to segments that encode alloantigenic sites and functional domains of beta3 in human beings.

The platelet glycoprotein complex alphaIIb beta3 is required for platelet-fibrinogen binding and platelet aggregation. This study was designed to characterize the nucleotide sequence of the canine platelet beta3 gene from cDNA. The nucleotide and deduced amino acid sequences of the canine beta3 gene were 92% and 96% homologous, respectively, with the sequences previously established for the beta3 gene of human beings. Within the beta3 gene, the nucleotide sequence of cDNA prepared from canine platelets shared homology of 89% for the cytoplasmic domain, 93% for the transmembrane domain, 92% for the extracellular domain, 94% for the arginine-glycine-aspartic acid (RGD) binding domain, and 97% for the region associated with Ca2+-dependent stabilization of the alphaIIb beta3 fibrinogen-binding pocket. The deduced amino acid sequence of canine beta3 was 100%, 97%, 96%, and 95% homologous with the cytoplasmic, transmembrane, extracellular, and RGD-binding domains, respectively, and was 100% homologous with the region associated with Ca2+-dependent stabilization of the alphaIIb beta3 fibrinogen-binding pocket of beta3 in human beings. The canine platelet cDNA signal peptide segment of the beta3 gene encodes for 22 amino acids, as compared with 26 amino acids previously reported for human beings. The deduced amino acid sequence of canine beta3 corresponds to the high-frequency allelic form for five of the six alloantigenic sites reportedly associated with human platelets: Leu33Leu40Pro407Arg489Arg636. The apparent amino acid residue in position 143 (Pen alloantigen) of canine platelet beta3 is histidine compared with arginine in human beings. Knowledge of the beta3 gene nucleotide sequence of normal dogs will facilitate the understanding of platelet alphaIIb beta3 structure-function relationships.

Amino Acid Sequence↗
PubMed1996

A platelet activation-specific monoclonal antibody that recognizes a receptor-induced binding site on canine fibrinogen.

An activation-specific monoclonal antibody (MoAb) termed "Canine Activated Platelet 1" (CAP1) has been developed and partially characterized. Flow cytometric studies of isolated canine platelets, using adenosine diphosphate (ADP) and platelet activating factor (PAF) as agonists, demonstrated that CAPI binding site number was proportional to agonist strength and agonist concentration. MoAb CAP1 binding was diminished by ethylenediamine-tetraacetic acid, suggesting that the antigen was either stabilized by calcium or antigen binding to the platelet surface was mediated by calcium. ADP-activated gel-filtered platelets also demonstrated reduced binding of MoAB CAP1 even in the presence of 1 mM CaCl2. Binding of MoAb CAP1 could be partially restored by activating gel-filtered platelets with PAF, suggesting that the antigen was either present within platelet granule membranes or was exposed after binding of released proteins(s) with a platelet receptor. A monoclonal antibody to human platelet glycoprotein IIIa (GPIIIa), which cross-reacts with canine platelet GPIIIa regardless of platelet activation status, did not inhibit binding of MoAb CAP1. MoAb CAP1 bound to isolated canine fibrinogen captured on polystyrene microtiter plates in the absence of platelet proteins. Immunoblots indicated that MoAb CAP1 recognizes nonreduced fibrinogen as well as a plasmin digest of isolated canine fibrinogen. Results of the present studies suggest that MoAb CAP1 recognizes a receptor-induced binding site on canine fibrinogen.

Animals↗
PubMed1996

Type I Glanzmann's thrombasthenia in a Great Pyrenees dog.

An 8-month-old female Great Pyrenees dog with chronic epistaxis and a history of gingival bleeding during shedding of deciduous teeth was evaluated for platelet function. Platelet morphology was normal at both the light and electron microscopic level. Platelet number and mean platelet volume were also normal. Platelet aggregation responses to adenosine diphosphate, collagen, platelet activating factor, and thrombin were markedly reduced, although shape change responses were normal. Clot retraction was markedly impaired. Monoclonal antibody (MoAb) Y2/51, a murine anti-human platelet beta 3 antibody that cross-reacts with canine platelet beta 3, and MoAb 5G11, a murine anti-dog platelet alpha IIb beta 3 antibody, bound minimally to affected dog platelets, as demonstrated by flow cytometry. Binding of MoAb Y2/51 was not detectable by immunoblot. MoAb CAP1, a murine anti-dog fibrinogen receptor-induced binding site antibody, failed to bind to affected dog platelets, as demonstrated by flow cytometry. A reduction in glycoproteins alpha IIb and beta 3 was demonstrated by two-dimensional protein electrophoresis. This is the first reported case of type I Glanzmann's thrombasthenia in the dog that closely resembles the clinical syndrome and the platelet morphology described in type I Glanzmann's thrombasthenia of human beings.

Animals↗
PubMed1996

STD screening. Practical tips.

General practitioners can contribute to community STD control by using the important tools of a sexual history, appropriate examination and tests. These screening tools allow early detection of disease, in 'high risk' people, accurate diagnosis of people with signs or symptoms, examination of sexual partners and the provision of preventive education and counselling.

Female↗
PubMed1994

Detection of activated feline platelets in platelet-rich plasma by use of fluorescein-labeled antibodies and flow cytometry.

Platelets contribute to prethrombotic or thrombotic states; however, accepted evaluation methods (i.e., in vitro testing by use of an aggregometer) of platelet function in cats can be difficult because of the large volume of blood required from which platelets are isolated and the potential for platelet activation due to difficult venipunctures in sometimes uncooperative or excited animals. The activation problem also contributes to errors in platelet counts. Platelets from four domestic short haired cats (two males, two females, 2-3 years old) minimally restrained without sedation or anesthesia were evaluated. Blood (5 ml) was collected by jugular venipuncture directly into syringes containing 3.8% trisodium citrate (nine parts blood to one part anticoagulant) plus prostaglandin E1 (3 microM; 0.25, 0.5, 1, or 2 microliters/500 microliters citrate) or 3.8% trisodium citrate alone. Prostaglandin E1, which is a stable metabolite of arachidonic acid with platelet inhibitory properties similar to those of prostaglandin I2, was added to the anticoagulant to prevent activation of platelets during the collection process. Feline platelets exposed to prostaglandin E1 became immediately and persistently nonreactive to agonists, which negated their use in functional studies (aggregation, 14C-serotonin release, binding of fluorescein-conjugated antifibrinogen) but improved platelet counting accuracy. Detection of in vivo activation of platelets in prethrombotic and thrombotic states in humans has been done by identification of activation-dependent molecules on platelet surfaces by use of specific antibody recognition and detection by flow cytometric analysis. Many activation-dependent platelet surface receptor changes are species specific; however, fibrinogen appears to be conserved across species.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Interrelated striated elements in vestibular hair cells of the rat.

Unusual fixation procedures revealed a series of interrelated striated organelles in type I and type II vestibular hair cells of the rat; these organelles seemed to be less well developed in cochlear hair cells. The findings suggest that contractile elements may play a role in sensory transduction in the inner ear, particularly in the vestibular system.

Actins↗
PubMed1983

Dye binding probes of lipid-binding structures. An investigation of 2-p-toluidinylnaphthylene-6-sulfonate binding to human and bovine prothrombin and fragment 1 in the presence and absence of calcium and magnesium ions.

TNS (2-p-toluidinylnaphthylene-6-sulfonate) binds to human and bovine prothrombin and Fragment 1 in the absence and presence of added Ca2+. The stoichiometry of TNS binding is 1:1 for human and bovine prothrombin and Fragment 1. The Ca2+-dependence of the fluorescence of TNS bound to bovine prothrombin Fragment 1 yields a modified Hill plot slope of 2.7, which is consistent with the slope obtained by monitoring the Ca2+ dependence of protein fluorescence quenching, CD changes and phospholipid binding. Mg2+ has have no effect on the fluorescence of TNS-prothrombin fluorescence. TNS binding to the amino-terminal region of prothrombin is the first relatively simple probe of the subtle and complex relationship which exists between protein structure and phospholipid binding.

Animals↗