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Biomedical subjects

Oana Vele

Publications and source records attributed to Oana Vele.

4 recordsLinked to original sources

Abnormalities of uterine cervix in women with inflammatory bowel disease.

AIM: To evaluate the prevalence of abnormalities of the uterine cervix in women with inflammatory bowel disease (IBD) when compared to healthy controls. METHODS: One hundred and sixteen patients with IBD [64 with Crohn's disease (CD) and 52 with ulcerative colitis (UC)] were matched to 116 healthy controls by age (+/- 2 years) at the time of most recent papanicolaou (Pap) smear. Data collected consisted of age, race, marital status, number of pregnancies, abortions/miscarriages, duration and severity of IBD, Pap smear results within five years of enrollment, and treatment with immunosuppressive drugs. Pap smear results were categorized as normal or abnormal including atypical squamous cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesion (LGSIL), and high-grade squamous intraepithelial lesion (HGSIL). RESULTS: The median age at the time of Pap smear was 46 (range: 17-74) years for the IBD group and matched controls (range: 19-72 years). There were more Caucasian subjects than other ethnicities in the IBD patient group (P = 0.025), as well as fewer abortions (P = 0.008), but there was no significant difference regarding marital status. Eighteen percent of IBD patients had abnormal Pap smears compared to 5% of controls (P = 0.004). Subgroup analysis of the IBD patients revealed no significant differences between CD and UC patients in age, ethnicity, marital status, number of abortions, disease severity, family history of IBD, or disease duration. No significant difference was observed in the number of abnormal Pap smears or the use of immunosuppressive medications between CD and UC patients (P = 0.793). No definitive observation could be made regarding HPV status, as this was not routinely investigated during the timeframe of our study. CONCLUSION: Diagnosis of IBD in women is related to an increased risk of abnormal Pap smear, while type of IBD and exposure to immunosuppressive medications are not. This has significant implications for women with IBD in that Pap smear screening protocols should be conscientiously followed, with appropriate investigation of abnormal results.

Adolescent↗

Alternatively spliced human tissue factor: a circulating, soluble, thrombogenic protein.

Tissue factor (TF) is an essential enzyme activator that forms a catalytic complex with FVII(a) and initiates coagulation by activating FIX and FX, ultimately resulting in thrombin formation. TF is found in adventitia of blood vessels and the lipid core of atherosclerotic plaques. In unstable coronary syndromes, plaque rupture initiates coagulation by exposing TF to blood. Biologically active TF has been detected in vessel walls and circulating blood. Elevated intravascular TF has been reported in diverse pro-thrombotic syndromes such as myocardial infarction, sepsis, anti-phospholipid syndrome and sickle-cell disease. It is unclear how TF circulates, although it may be present in pro-coagulant microparticles. We now report identification of a form of human TF generated by alternative splicing. Our studies indicate that alternatively spliced human tissue factor (asHTF) contains most of the extracellular domain of TF but lacks a transmembrane domain and terminates with a unique peptide sequence. asHTF is soluble, circulates in blood, exhibits pro-coagulant activity when exposed to phospholipids, and is incorporated into thrombi. We propose that binding of asHTF to the edge of thrombi contributes to thrombus growth by creating a surface that both initiates and propagates coagulation.

Alternative Splicing↗

Local shear conditions and platelet aggregates regulate the incorporation and activity of circulating tissue factor in ex-vivo thrombi.

The presence of thrombogenic blood-borne or circulating tissue factor (cTF) has recently been demonstrated. These observations have implicated cTF to be a key determinant of thrombus propagation by depositing on platelets in nascent thrombi. Previously, we detected cTF by detergent solubilization and addition of phospholipids. We now report the direct demonstration of TF activity in ex-vivo thrombi. Collagen-coated substrates were exposed to native blood at shear rates of 0, 650, and 2,000 s(-1) for 10 min in a modified rotating Teflon cone and plate viscometer. Substrates were then gently rinsed to remove 'loose' (unadherent) components of blood. cTF activity was measured by adding a solution containing 10 nM FVIIa, 100 nM FX, and 5 mM CaCl(2) to the substrates exposed to blood. Samples of this mixture were obtained at intervals for 30 min and the amount of Xa generated was quantified by adding a chromogenic substrate, Spectrozyme Xa, and measuring the increase in OD at 405 nm. Our studies show that a minimal amount of generated Xa (approximately 1nM) can be measured from ex-vivo thrombi. Static and shear samples generated the same amount of Xa, with the exception of blood subjected to 650 s(-1) shear. At 650 s(-1) shear rate, the amount of Xa generated reached a maximum of 4 nM at 5 min and then decreased to approximately 1 nM. Immunohistological stains and fluorescent images demonstrate the presence of cTF antigen at 650 s(-1) wall shear rate.

Collagen↗