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1.  Fibrinogen Hershey IV: A Novel Dysfibrinogen with a γ V411I Mutation in the Integrin αIIbβ3 Binding Site 
Thrombosis and haemostasis  2008;99(6):1008-1012.
The carboxyl terminal segment of the fibrinogen γ chain from γ 408–411 plays a crucial role in platelet aggregation via interactions with the platelet receptor αIIbβ3. We describe here the first naturally-occurring fibrinogen point mutation affecting this region and demonstrate its effects on platelet interactions. DNA sequencing was used to sequence the proband DNA, and platelet aggregation and direct binding assays were used to quantitate the biological effects of fibrinogen Hershey IV. The Hershey IV proband was found to be heterozygous for two mutations, γ V411I and γ R275C. Little difference in aggregation was seen when fibrinogen Hershey IV was compared to normal fibrinogen. However, less aggregation inhibition was observed using a competing synthetic dodecapeptide containing the V411I mutation as compared to the wild-type dodecapeptide. Purified fibrinogen Hershey IV also bound to purified platelet αIIbβ3 with a lower affinity than wild-type fibrinogen. These findings show that the γ V411I mutation results in a decreased ability to bind platelets. In the heterozygous state, however, the available wild-type fibrinogen appears to be sufficient to support normal platelet aggregation.
PMCID: PMC4089099  PMID: 18521501
Fibrinogen/fibrin; GP IIb/IIIa; inherited coagulation disorders; integrins; platelet glycoproteins
2.  Targeted Next-Generation Resequencing of F5 Gene Identifies Novel Multiple Variants Pattern in Severe Hereditary Factor V Deficiency 
Case Reports in Genetics  2013;2013:941684.
The present study investigated the genetic defects underlying severe Factor V deficiency in a 26-year-old Columbian (South America) female and her immediate family (both parents and newborn child) by next generation sequencing (NGS) of the entire F5 gene locus. Five mutations in the coding sequence of F5, including three missense single-nucleotide variants (R2102H, R513K, D107H) and two synonymous variants (A135A , S184S), were identified and confirmed by the Sanger sequencing in the investigated proband (homozygote for all detected mutations), her parents, and her newborn child (all heterozygotic carriers for identified mutations). Each of the three missense variants was previously associated with separate phenotypes, including Factor V deficiency (R2102H), thrombosis (R513K) and frequent miscarriages (D107H). In addition, at least 75 additional single-nucleotide variants (including six novels) were identified in untranslated region of F5.
PMCID: PMC3639706  PMID: 23662219
3.  Heparin-Induced Thrombocytopenia Associated with Massive Intracardiac Thrombosis: A Case Report 
Case Reports in Hematology  2012;2012:257023.
A 60-years old patient was admitted to a community hospital with septic arthritis. He was treated with antibiotics and subcutaneous unfractionated heparin (UH) was used for venous thromboprophylaxis. After three days, he developed leg deep venous thrombosis and was treated with IV heparin. One day later, the patient developed pulmonary emboli, which was found using ventilation/perfusion scan. He was transferred to the University Hospital for further management. Upon arrival, antibiotic and intravenous UH were continued. Trans-Esophageal Echocardiogram showed a thrombus in the right atrium, a small portion of which extended to the left atrium through a patent foramen ovale. Another large thrombus was noted in the right ventricle, which extended to the pulmonary artery. Review of the patient's medical records revealed a halving of his platelet count three days following the heparin administration. Therefore, HIT seemed very likely. Intravenous UH was stopped and an emergency thrombectomy was performed. ELISA testing of HIT antibodies came negative. This made HIT diagnosis unlikely and the patient received dalteparin. A week later, as the platelet count declined again, HIT antibodies' testing using ELISA and C-14 serotonin release was repeated, and both assays were positive. Argatroban was restarted and the platelet count normalized.
PMCID: PMC3420555  PMID: 22937322
4.  The effect of ozone exposure on the ability of human surfactant protein a variants to stimulate cytokine production. 
Ozone exposure can cause inflammation and impaired lung function. Human surfactant protein A (SP-A) may play a role in inflammation by modulating cytokine production by macrophages. SP-A is encoded by two genes, SP-A1 and SP-A2, and several allelic variants have been characterized for each gene. These allelic variants differ among themselves in amino acids that may exhibit differential sensitivity to ozone-induced oxidation and this may produce functional differences. We studied the effects of SP-A variants before and after ozone exposure on the production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-8. These are important proinflammatory cytokines and are expressed by the macrophage-like THP-1 cells. Eight variants were expressed in vitro, characterized by gel electrophoresis, and studied. These included six single-gene SP-A alleles and two SP-A variants derived from both genes. Variants were exposed to ozone at 1 ppm for 4 hr at 37 degrees C, and we compared their ability to stimulate cytokine (TNF-alpha and IL-8) production by THP-1 cells to air-exposed and unexposed SP-A variants. We found that a) SP-A2 variants (1A, 1A(0), 1A(1) stimulate significantly more TNF-alpha and IL-8 production than SP-A1 variants (6A, 6A(2), 6A(4); b) coexpressed SP-A variants (1A(0)/6A(2), 1A(1)/6A(4) have significantly higher activity than single gene products; c) after ozone exposure, all SP-A variants showed a decreased ability to stimulate TNF-alpha and IL-8 production, and the level of the decrease varied among SP-A variants (26-48%); and d) human SP-A from patients with alveolar proteinosis exhibited a minimal decrease (18% and 12%, respectively) in its ability to stimulate TNF-alpha and IL-8 after in vitro ozone exposure. We conclude that biochemical and functional differences exist among SP-A variants, that ozone exposure modulates the ability of SP-A variants to stimulate cytokines by THP-1 cells, and that SP-As from bronchoalveolar lavage (BAL) fluid of certain alveolar proteinosis patients may be oxidized in vivo.
PMCID: PMC1240696  PMID: 11781168

Results 1-4 (4)