These results indicate that high variability of cytokine concentrations and low frequency of their detection in serum samples from periodontitis patients make these determinations useless for the detection of disease presence and/or its severity. In contrast, high absolute levels of IL-1beta, TNF-alpha, IL-2 and IFN-gamma and, especially their high ratios to IL-4 and IL-10 found in inflamed tissue biopsies, were closely associated with periodontal disease severity.
In patients with the severe form of chronic periodontitis, it seems that clinical attachment loss is not associated with bacterial permeability into coronary vessels. What is important is the presence of an active inflammatory process expressed by a significantly higher bleeding index in those patients in whom the examined bacterial species were found in atherosclerotic plaque.
Summary. Background: Vitamin K epoxide reductase subunit 1 (VKORC1) is the molecular target of coumarin anticoagulants and mutations in VKORC1 have been identified previously in individuals who required high warfarin doses. Objective: Detailed characterization of the relationship between variation in VKORC1 and the warfarin resistance phenotype. Patients and methods: Serum warfarin concentration and coagulation parameters were determined in 289 subjects who required warfarin doses >20 mg day )1. The VKORC1 sequence was studied in selected study subjects. Results: Twenty-eight out of 289 (10%) subjects had serum warfarin >2.3 mg L )1 during stable therapeutic anticoagulation indicating pharmacodynamic warfarin resistance. Detailed analysis of 15 subjects from this group showed that eight out of 15 (53%) had nucleotide substitutions in VKORC1 predictive of p.V66M, p.L128R, p.V54L or p.D36Y. VKORC1 was normal in the remaining seven out of 15 (47%) subjects and in nine out of nine (100%) subjects with high warfarin dose requirement not caused by pharmacodynamic resistance. At referral, subjects with VKORC1 mutations received a median warfarin dose of 32 mg day )1(range 22-55) and had a median serum warfarin concentration of 4.6 mg L )1 (range 2.6-9.0). VKORC1 substitutions were associated with a requirement for high warfarin doses but not with adverse clinical events. Family members with VKORC1 nucleotide substitutions and not receiving warfarin had undetectable PIVKA-II and K 1 epoxide (K 1 O). Conclusions: Nucleotide variations in VKORC1 are a common cause of pharmacodynamic warfarin resistance but are not associated with adverse outcome during anticoagulation. Mutations associated with warfarin resistance do not cause a discernible defect in VKORC1 reductase function.
Vitamin K is required for the ɣ-carboxylation of specific glutamic acid residues within the Gla domain of the 17 vitamin K-dependent proteins (VKDPs). The timely detection and correction of vitamin K deficiency can protect against bleeding. Vitamin K also plays a role in bone metabolism and vascular calcification. Patients at increased risk of vitamin K deficiency include those with a restricted diet or malnutrition, lipid malabsorption, cancer, renal disease, neonates and the elderly. Coagulation assays such as the prothrombin time have been used erroneously as indicators of vitamin K status, lacking sufficient sensitivity and specificity for this application. The measurement of phylloquinone (K1) in serum is the most commonly used marker of vitamin K status and reflects abundance of the vitamin. Concentrations <0.15 µg/L are indicative of deficiency. Disadvantages of this approach include exclusion of the other vitamin K homologues and interference from recent dietary intake. The cellular utilisation of vitamin K is determined through measurement of the prevalence of undercarboxylated VKDPs. Most commonly, undercarboxylated prothrombin (Protein Induced by Vitamin K Absence/antagonism, PIVKA-II) is used (reference range 17.4–50.9 mAU/mL (Abbott Architect), providing a retrospective indicator of hepatic vitamin K status. Current clinical applications of PIVKA-II include supporting the diagnosis of vitamin K deficiency bleeding of the newborn, monitoring exposure to vitamin K antagonists, and when used in combination with α-fetoprotein, as a diagnostic marker of hepatocellular carcinoma. Using K1 and PIVKA-II in tandem is an approach that can be used successfully for many patient cohorts, providing insight into both abundance and utilisation of the vitamin.
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