Thyroid parameters variations in healthcare workers and students exposed to low-dose ionizing radiations.

SUMMARY: Background. Ionizing Radiations (IR) are an important occupational risk factor for the potential damage that can cause to workers' health and for their presence in numerous professional settings. Health care workers (HCW) can be exposed to IR from various sources, in particular from x-rays using radiological equipment, and represent the largest group of workers occupationally at risk, despite increased regulation and protection which caused exposure to low dose radiations. The thyroid gland is one of the most sensitive organs to damage and an important target of IR, leading to functional and organic diseases. The aim of this study is to assess the variations in thyroid hormones, in a population of HCW exposed to low-dose IR. Methods. 121 individuals of the Teaching Hospital Policlinico Umberto I in Rome exposed to low-dose of IR (78 HCW, 17 Residents and 26 Radiology Technicians Students) were observed assessing serum levels of different thyroid function parameters as free triiodothyronine, free thyroxine and thyroid stimulating hormone at T1, T2 and DeltaT. Age, gender, history of thyroid diseases, BMI and smoke were analyzed as possible influencing factors using linear and multiple logistic regression analysis. Results. Analyzing TSH, fT3 and fT4 serum levels, in two different measurement (T1 and T2) and considering Delta between them, adjusting for different confounding factors, data showed no variation of TSH levels related to occupational exposure, a decrease of fT3 hormone values in HCW and residents, and an increase of fT4 in HCW. Discussion. The analysis of our results revealed that hospital occupation has an impact on thyroid hormones variations, with an increase of fT4 and a decrease of fT3 and no variations of TSH. These results are in conflict with previous studies evidences, in which both free hormones decreased with a concomitant increase of TSH. Conclusion. Exposure to low dose IR influences levels of free thyroid hormones, with no variation in TSH, which could result in a functional or organic disease. For this reason it is recommended continuous surveillance through a periodic check of all the thyroid hormones for an overall view of each HCW. However, further studies are necessary to confirm hormones trend and assess any related thyroid diseases.

Tooth extraction without discontinuation of oral antithrombotic treatment: A prospective study.

OBJECTIVE: To identify which variable, among those related to surgeries, to patients, or to antithrombotic treatments, could be considered as a bleeding indicator, and to analyze effectiveness of the local hemostatic protocols used, incidence of bleeding and healing index, depending on the number of extracted teeth, and patient antithrombotic treatment. METHODS: Patients who underwent tooth extractions without interruption or reduction of antithrombotic treatment were prospectively followed. The exact two-tailed Fisher test was used to investigate the relationship between presence/absence of bleeding and type of hemostatic material. The effect of variables on the probability of bleeding and healing index was assessed by means of a multivariate logistic regression. RESULTS: Two hundred and fifty-four procedures were analyzed. The incidence of bleeding was 15.75%. Severe bleeding occurred in only 6 patients (2.34%). The number of involved dental quadrants and pre-surgical antibiotic treatments were found to be positively related with bleeding. The use of vasoconstrictors during surgery resulted in a reduction of healing index scores. CONCLUSIONS: Tooth extractions in patients on antithrombotic treatment were found to be free from significant bleeding although the involvement of more than 1 quadrant in the same procedure should be avoided.

Rivaroxaban vs warfarin in high-risk patients with antiphospholipid syndrome.

Rivaroxaban is an effective and safe alternative to warfarin in patients with atrial fibrillation and venous thromboembolism. We tested the efficacy and safety of rivaroxaban compared with warfarin in high-risk patients with thrombotic antiphospholipid syndrome. This is a randomized open-label multicenter noninferiority study with blinded end point adjudication. Rivaroxaban, 20 mg once daily (15 mg once daily based on kidney function) was compared with warfarin (international normalized ratio target 2.5) for the prevention of thromboembolic events, major bleeding, and vascular death in patients with antiphospholipid syndrome. Only high-risk patients triple positive for lupus anticoagulant, anti-cardiolipin, and anti-ß2-glycoprotein I antibodies of the same isotype (triple positivity) were included in the study. The trial was terminated prematurely after the enrollment of 120 patients (59 randomized to rivaroxaban and 61 to warfarin) because of an excess of events among patients in the rivaroxaban arm. Mean follow-up was 569 days. There were 11 (19%) events in the rivaroxaban group, and 2 (3%) events in the warfarin group. Thromboembolic events occurred in 7 (12%) patients randomized to rivaroxaban (4 ischemic stroke and 3 myocardial infarction), whereas no event was recorded in those randomized to warfarin. Major bleeding occurred in 6 patients: 4 (7%) in the rivaroxaban group and 2 (3%) in the warfarin group. No death was reported. The use of rivaroxaban in high-risk patients with antiphospholipid syndrome was associated with an increased rate of events compared with warfarin, thus showing no benefit and excess risk. This trial was registered at www.clinicaltrials.gov as #NCT02157272.

Antithrombotic therapy with rivaroxaban in five patients with paroxysmal nocturnal haemoglobinuria and thrombotic events.

Five patients with paroxysmal nocturnal haemoglobinuria and thrombotic complications under oral antithrombotic treatment with vitamin K antagonist were switched to receive the direct oral anticoagulant rivaroxaban an factor Xa inhibitor. In all five patients haematological and biochemical parameters and adverse events were evaluated for a period of twelve months. Therapy with rivaroxaban was well tolerated in all cases and one patient showed a significant reduction of bleeding and transfusion requirement. All patients obtained a significant reduction in days of hospitalization with a consequent improvement in their quality of life after rivaroxaban treatment.

The Use of a Chitosan-Derived Hemostatic Agent for Postextraction Bleeding Control in Patients on Antiplatelet Treatment.

PURPOSE: The current approach for tooth extraction in patients receiving antiplatelet treatment requires the use of local hemostatic agents without previous thromboembolic treatment interruption. The aim of the present study was to evaluate the effectiveness of an extra-alveolar hemostatic agent, the HemCon Dental Dressing (HDD), in controlling postsurgical bleeding. MATERIALS AND METHODS: Routine, atraumatic tooth extractions were performed in a single session under local anesthesia without a vasoconstrictor and without interruption of antiplatelet therapy. All patients underwent extraction of 2 teeth in the same session, with each in a different dental hemi-arch, and the hemostatic method to be used was randomly chosen: in the test site, the HDD was applied, whereas in the control site, a common hemostatic sponge (CollaPlug, Zimmer Dental) was applied and stabilized in situ with a suture. For each surgery, 2 different times were measured: the time required for hemostatic agent application and the time required for hemostasis achievement. Postoperative pain and healing quality also were evaluated. RESULTS: Twenty outpatients were enrolled. The mean application time was considerably shorter in the test group than in the control group; the mean bleeding time in the control group was considerably shorter than in the test group; pain values were lower in the test group than in the control group, especially at suture removal; and postextraction socket healing was better in the test group than in the control group. CONCLUSION: HDD seems to be a valid and safe alternative in treating postextraction sockets in outpatients under single-drug antiplatelet treatment in the absence of surgical wound lacerations.

Hereditary protein C deficiency and thrombosis risk: genotype and phenotype relation in a large Italian family.

UNLABELLED: Protein C (PC) deficiency is an autosomal dominant inherited disorder associated with spontaneous and recurrent thrombotic events. Factor V Leiden (FVL) increases the risk of thrombosis in PC-deficient type I families. We have investigated the relationship between PC deficiency genotype and clinical phenotype in a large four-degree Italian family followed since 1988. METHODS: PC activity and antigen levels were quantified; sequencing of PC DNA was performed to identify polymorphism. FVL and factor II (G20210A) polymorphism were screened. RESULTS: PC activity ranged from 5% to 9%, and PC antigen levels were 5,3% in two homozygous for PROC missense mutation Arg32Cys; PC activity ranged from 18% to 60% and antigen levels from 21% to 64%, respectively, in 11 heterozygous for Arg32Cys; PC activity was 99% and 120% in two wild type. Of 15, eight were heterozygous for FVL. The two subjects with PC < 6%, homozygous for Arg32Cys and heterozygous for FVL, suffered from thrombosis during childhood. Of 11, six subjects with PC deficiency and heterozygous for FVL showed the first thrombosis at an age between 21 and 54. None of the five PC-deficient subjects, who were wild type for FVL, showed thrombosis. Two subjects with PC > 70%, both heterozygous for FVL developed thrombosis in the presence of another risk factor. This study suggests that FVL and PROC mutations increase the risk of thrombosis in subjects with PC deficiency, which could be considered as a 'variable' risk factor. The thrombosis-prone PC-deficient families carry additional risk factors for thrombosis.

Oral anticoagulant therapy in Italian patients 80 yr of age or older with atrial fibrillation: a pilot study of low vs. standard PT/INR targets.

BACKGROUND: Oral anticoagulation therapy (OAT), which aims to prevent thromboembolism in patients with atrial fibrillation (AF), is underused in subjects who are over the age of 80 yr because of the associated bleeding risk. The aim of this study was to evaluate the efficacy and safety of OAT with low (2.0) vs. standard (2.5) PT/international normalised ratio (INR) targets in patients over the age of 80. MATERIALS AND METHODS: Of 233 patients aged 80 yr or older with AF on OAT, 58 had unstable PT/INR values and achieved reduced targets. These patients were enrolled as a group (A) in a case-control study and were treated with a low (2.0) PT/INR target. They were compared with a second group (B) of 58 additional patients who were matched for age and CHADS scores and treated with a standard (2.5) PT/INR target. Group A OAT parameters were also compared before and after the PT/INR reduction. The time in the therapeutic range (TTR%), PT/INR values >5, haemorrhages and strokes were prospectively evaluated in the two groups after 2 yr of follow-up. RESULTS: Of the 116 enrolled patients, 55 group A and 57 group B patients were evaluated. The TTR was 72.59% in group A and 64.43% in group B (P < 0.01). The percent of PT/INR values >5 was 0.68% for group A and 1.42% for group B (P < 0.05). Haemorrhages and thromboses occurred only in group B patients. The before and after analysis in group A showed that a low INR target produced an increase in the TTR (53.05% vs. 72.59%; P < 0.0001) and a reduction in the PT/INR values > 5 (1.72% vs. 0.68%; P < 0.001). CONCLUSIONS: A low PT/INR target seems effective and safe in Italian patients with AF over the age of 80. Further trials are needed to confirm the hypothesis generated by this study.

Is telephone follow-up useful in preventing post-extraction bleeding in patients on antithrombotic treatment?

BACKGROUND: The aim of the study was to investigate the usefulness of telephone follow-up in preventing post-extraction bleeding and improving wound healing in patients on chronic antithrombotic treatment. MATERIAL AND METHODS: A prospective randomized clinical trial was carried out on 256 patients (test group = 128; control group = 128). The exact two-tailed Fisher test and the two-tailed non-parametric Mann-Whitney test were used for statistical analysis. RESULTS: The incidence of post-extraction bleeding was 15.6% and there was no difference between test and control groups. However, the study group was significantly, though weakly, associated with the severity of bleeding. Patient satisfaction with post-operative follow-up differed significantly between patients who had and those who did not have post-extraction bleeding. CONCLUSIONS: Telephone follow-up after tooth extraction may play a role in the prevention of severe post-operative bleeding as well as in monitoring and managing the surgical wound. Key words:Post-operative instructions, patient satisfaction, wound healing.

Trial of Rivaroxaban in AntiPhospholipid Syndrome (TRAPS): Two-year outcomes after the study closure.

BACKGROUND: Trial of Rivaroxaban in AntiPhospholipid Syndrome was a prospective randomized, open-label, noninferiority study conducted in 14 centers in Italy. Rivaroxaban was compared with warfarin for the prevention of thromboembolic events, major bleeding, and vascular death in high-risk, triple-positive patients with antiphospholipid syndrome. OBJECTIVE: The aim of this paper is to report the events during the 2-year follow-up after the study closure. METHODS: On January 28, 2018, the trial was prematurely stopped by adjudication and safety committee for an excess of events in the rivaroxaban group. Randomized patients were advised on trial results and those randomized to rivaroxaban were solicited to switch to warfarin. All 14 participating centers were asked and accepted to follow their patients for clinical events. This report describes the rate of events that occurred between January 28, 2018, and January 28, 2020. RESULTS: Of 120 randomized patients, 115 were available for follow-up. Outcome events were two in six (33.3%) patients who remained on direct oral anticoagulants (DOACs) and six in 109 (5.7%) patients on warfarin (hazard ratio [HR] 6.9; 95% confidence interval [CI] 1.4-34.5, P = .018). The two patients on DOACs (one taking dabigatran and one taking rivaroxaban) suffered from thromboembolic events, whereas of the six patients with composite outcomes on warfarin, three had thromboembolic events (HR for thrombosis 13.3; 95% CI 2.2-79.9, P = .005). CONCLUSION: These data further support the use of warfarin in high-risk patients with antiphospholipid syndrome.

Vitamin K Concentration and Cognitive Status in Elderly Patients on Anticoagulant Therapy: A Pilot Study.

OBJECTIVES: Recent studies have suggested that vitamin K may exert significant effects on the central nervous system. The present study investigates the relationship between vitamin K plasmatic levels and cognitive functions in elderly patients on oral anticoagulant therapy (OAT). DESIGN: At the Thrombosis Centre of Haematology, "Sapienza" University of Rome, 85 patients on OAT, aged between 75 and 92, were randomly enrolled in the study. Patients were on OAT with vitamin K antagonists (VKAs). Vitamin K1 concentrations were determined using standardized High-Performance Liquid Chromatography (HPLC). Cognitive functions were assessed using the Milan Overall Dementia Assessment (MODA). RESULTS: MODA scores are positively correlated to vitamin K1 concentration. Patients with vitamin K1 below 0.100 µg/L and between 0.100 and 0.400 µg/L and between 0.100 and 0.400 µg/L and between 0.100 and 0.400 p < 0.001). Even long-term OAT (>10 years) does not affect MODA scores. Education seems to exert a greater role on the cognitive status in comparison with aging. CONCLUSIONS: The study shows a positive association between vitamin K1 concentration and cognitive status in elderly patients (≥75 years) on OAT. The relationship between vitamin K1 concentration and MODA scores is described by a linear model. Cognitive status is not influenced by the duration of OAT but by the years of education.

Correction to: Plasma Vitamin K1 Levels in Italian Patients Receiving Oral Anticoagulant Therapy for Mechanical Heart Prosthesis: A Case-Control Study.

Throughout the manuscript the units of plasma vitamin K1 concentration which previously read.

The Relationships Between Vitamin K and Cognition: A Review of Current Evidence.

Vitamin K is a fat-soluble nutrient discovered in 1935 and its role in blood coagulation has been thoroughly explored. In recent years, studies conducted in vitro and on animals highlighted vitamin K involvement in brain cells development and survival. In particular, vitamin K seems to have an antiapoptotic and anti-inflammatory effect mediated by the activation of Growth Arrest Specific Gene 6 and Protein S. Moreover, this vitamin is involved in sphingolipids metabolism, a class of lipids that participate in the proliferation, differentiation, and survival of brain cells. An altered expression in sphingolipids profile has been related to neuroinflammation and neurodegeneration. This review stems from a growing interest in the role of vitamin K in brain functions, especially in cognition, also in view of an expected increase of prevalence of Alzheimer's disease and other forms of dementia. It collects recent researches that show interesting, even though not definitive, evidence of a direct correlation between vitamin K levels and cognitive performance. Moreover, vitamin K antagonists, used worldwide as oral anticoagulants, according to recent studies may have a negative influence on cognitive domains such as visual memory, verbal fluency and brain volume. The aim of this review is to analyze the evidence of clinical studies carried out up to date on the relationship between vitamin K intake and cognitive performances. The involvement of vitamin K antagonists (VKAs) in declining cognitive performances is also addressed separately.

Anticoagulant therapy with fondaparinux in a liver transplant patient with thrombosis and liver fibrosis: a case report.

The treatment with fondaparinux is the effective and safe anticoagulant therapy in liver transplant patient on immunosuppressive therapy with arterial thrombosis, and it seems able to reduce liver fibrosis. Although this treatment is not generalizable, further prospective large studies need to confirm this case report.

Plasma Vitamin K1 Levels in Italian Patients Receiving Oral Anticoagulant Therapy for Mechanical Heart Prosthesis: A Case-Control Study.

BACKGROUND: Oral anticoagulant therapy (OAT) with a vitamin K antagonist (VKA) is the choice of treatment for preventing thromboembolism in patients with mechanical heart valve prosthesis (MHP). The percentage of time in the therapeutic range (TTR%) expresses the OAT quality. We planned a case-control study in order to determine vitamin K1 plasmatic concentrations in MHP patients and to correlate these with TTR%. MATERIALS AND METHODS: Of 756 MHP patients receiving OAT, 125 patients (61 younger than 65 years, and 64 older than 65 years) and 120 healthy blood donors, matched for sex and age, were enrolled in the study. All subjects completed a living questionnaire regarding diet, and underwent blood collection. Vegetable and fruit intake was categorized as optimal or suboptimal, and the high-performance liquid chromatography method was used to determine vitamin K1 levels. RESULTS: Neither the patients nor controls had been taking vitamin supplements prior to the start of the study. The median vitamin K1 level was 290 pg/mL in 72 controls with optimal intake, and 274 pg/mL in 48 controls with suboptimal intake, while the median vitamin K1 level in MHP patients with optimal intake was 409 pg/mL, significantly higher (p < 0.001) than the 133.5 pg/mL in patients with suboptimal intake. Vitamin K1 concentration in MHP patients appears to be linked to an age-related threshold: in patients younger than 65 years of age, the median vitamin K1 level was 431 pg/mL, significantly higher (p < 0.05) than the 290 pg/mL in patients older than 65 years of age. No clear relation was found between vitamin K1 levels and TTR% (Pearson = 0.14). However, patients with vitamin K1 >160 pg/mL showed a TTR% >60 %. Among patients younger than 65 years, subjects with vitamin K1 >160 pg/mL showed a median TTR of 66 %, this being significantly higher (p < 0.001) than the 46 % level shown by patients with vitamin K1 <160 pg/mL. CONCLUSIONS: Vitamin K1 concentrations in MHP patients seem to be related to both diet and age.

The effectiveness of a new method using an extra-alveolar hemostatic agent after dental extractions in older patients on oral anticoagulation treatment: an intrapatient study.

OBJECTIVE: The present study aimed to evaluate the effectiveness of a new adhesive agent, HemCon Dental Dressing (HDD), in patients receiving oral anticoagulant treatment (OAT), who were undergoing nonsurgical tooth extractions without interruption or reduction of OAT, compared with that of a common local hemostatic agent. STUDY DESIGN: Twenty patients on OAT with an international normalized ratio (INR) ranging between 1.6 and 3.5 were recruited. In the same session, each patient was subjected to the extraction of two teeth: In the test site the HDD was applied, and in the control site, a common hemostatic sponge (CollaPlug, Zimmer Dental) was used. RESULTS: The mean application time was significantly lower in the test group than in the control group, and this difference is statistically significant. The mean postoperative pain was significantly lower in the test group than in the control group the morning after surgery and at the time of suture removal. Post-extraction socket healing was significantly better in the test group than in the control group. CONCLUSIONS: Tooth extraction in patients receiving OAT and have an INR lower than 3.5 is a safe procedure without discontinuation of the OA regimen. The HDD seems to reduce postoperative side effects and obtain rapid soft tissue healing.

Anticoagulant therapy with rivaroxaban in a young patient with paroxysmal nocturnal hemoglobinuria.

The new direct oral anticoagulants such us rivaroxaban, could play an important role in the anticoagulant treatment of patients with paroxysmal nocturnal hemoglobinuria where anticoagulant treatment is complex to run, since they have shown a reduction in serious bleeding complications compared to antithrombotic therapy with classical vitamin k antagonist.

Effectiveness and safety of therapy with vitamin K antagonists in Italian patients aged 80 years or older: a multicentre retrospective study comparing the Zeus algorithm with the PARMA algorithm or manual therapy.

BACKGROUND: The use of oral anticoagulant therapy (OAT) has constantly increased in the prevention of thromboembolism, particularly in patients 80 years of age or older. OBJECTIVE: The aim of this multicentre study was to evaluate the efficacy and safety of vitamin K antagonists (VKAs) in elderly patients managed with a computer dosing algorithm compared with a dosage decided by expert physicians. MATERIALS AND METHODS: Nine Italian thrombosis centres utilising the Zeus dosing algorithm were involved. The before-after study enrolled patients managed firstly by medical staff (manual system) or with the PARMA algorithm for 12 months from July 2008 to June 2009 and then with the Zeus algorithm during the analogous period from 2010 to 2011. Of 7605 patients in the OAT maintenance phase, 2281 were older than 80 years (mean age 84.2 years). Data for these 2281 patients managed with both modalities were analysed. RESULTS: Of the 2281 patients 80 years of age or older, 1776 underwent OAT for atrial fibrillation (AF). Use of a dosing algorithm increased the OAT quality: time in therapeutic range (TTR) was significantly (p < 0.001) higher during the Zeus period than during the manual period (71.6 vs. 68.8 %). The TTR achieved with Zeus was similar to that obtained with the PARMA algorithm. In addition, patients managed with Zeus took a weekly drug dosage significantly (p < 0.01) lower than that both suggested by PARMA and prescribed by expert physicians, with a reduced number of adverse events. CONCLUSIONS: This study confirms that the effectiveness and safety of VKA therapy in patients 80 years of age or older increases with computer dosing algorithms.

Rapid, high performance method for the determination of vitamin K(1), menaquinone-4 and vitamin K(1) 2,3-epoxide in human serum and plasma using liquid chromatography-hybrid quadrupole linear ion trap mass spectrometry.

Unlike the other fat-soluble vitamins, vitamin K circulates in the human bloodstream at very low levels because of a low intake in the diet. Mammals have developed an efficient recycling system, known as vitamin K-epoxide cycle, which involve quinone, hydroquinone and epoxide forms of the vitamin. Phylloquinone (K(1)) is the main homologue, while menaquinone-4 (MK-4) is both a member of the vitamin K(2) family and metabolite of K(1) in extra-hepatic tissues. Notwithstanding the recent advances, many aspects of the complex vitamin K physiology still remain to be investigated. Therefore, there is a critical need to develop more reliable analytical methods for determining the vitamin K and its metabolites in biological fluids and tissues. Nevertheless, relatively low concentrations, unavailability of some authentic standards and occurrence of interfering lipids make this a challenging task. The method proposed in the present paper can directly and accurately estimate K(1), K(1) 2,3-epoxide (K(1)O), and MK-4 in human serum and plasma at concentrations in the ng/L-µg/L range, using labelled internal standards and a quadrupole linear ion trap instrument operated in multiple reaction monitoring (MRM) mode. High sensitivity was achieved by removing signal "endogenous suppressors" and making the composition of the non-aqueous mobile phase suitable to support the positive atmospheric pressure chemical ionization of the analytes. An excellent selectivity resulted from the combination of some factors: the MRM acquisition, the adoption of an identification point system, an extraction optimized to remove most of the lipids and a tandem-C18 column-system necessary to separate isobaric interferences from analytes. The method was validated according to the Food and Drug Administration (FDA) guidelines and its accuracy was assessed by analysing 9 samples from the Vitamin K External Quality Assessment Scheme (KEQAS). Its feasibility in evaluating vitamin K status in human serum was also tested by monitoring a group of six healthy subjects and a group of six patients under oral anticoagulant therapy (OAT). Warfarinised patients did not show deficiency of K1 but levels comparable with those of healthy people and an accumulation of K1O up to 3.760µg/L. MK-4 was not detected in either of the two groups.

Thrombophilic screening in young patients (< 40 years) with idiopathic ischemic stroke: a controlled study.

INTRODUCTION: Despite extensive clinical and laboratory investigations, the etiology of ischemic stroke remains unknown in approximately one third of patients. MATERIALS AND METHODS: Thirty-four consecutive patients less than 40 years old (Males 13, Females 21, mean age 26.6 years, range 2-39) with documented ischemic stroke underwent, one year after the acute event, laboratory evaluation of antithrombin, protein C, free and total protein S, activated protein C resistance, fibrinogen, factor VII:C, homocysteine levels and antiphospholipid antibodies (APA). Moreover, prevalence of F5 R506Q, F2 G2021A and homozygosis for thermolabile variant C677T of the methylenetetrahydrofolate reductase (MTHFR) were also evaluated and compared to the results obtained in 120 normal controls. RESULTS: Antithrombin and protein C levels resulted normal in all cases. One patient (2.9%) showed free protein S deficiency and 3 patients (8.8%) had activated protein C resistance. Homocysteine levels above 15 µmol/L were found in one patient (2.9%). APA were found in 21 patients (61.7%) and in only 2 out of 120 (1.66%) controls (OR=95.31; 95% C.I.: 18.22-667.81). The multivariate analysis selected that the presence of APA was significantly associated with an increased risk of stroke (OR=156.60; 95% C.I.: 25.99-943.47) in this cohort of patients. The combination between APA and cardiovascular risk factors determined a risk of 29-fold (OR=29.31; 95% CI: 3.28-261.69). DISCUSSION: Our data suggest that the presence of APA is associated with an increased risk of idiopathic ischemic stroke in young patients. Furthermore, also the combination of APA and cardiovascular risk factors is significantly associated with development of idiopathic ischemic stroke.

Effects of folic acid deficiency and MTHFR C677T polymorphism on spontaneous and radiation-induced micronuclei in human lymphocytes.

Folic acid plays a key role in the maintenance of genomic stability, providing methyl groups for the conversion of uracil to thymine and for DNA methylation. Besides dietary habits, folic acid metabolism is influenced by genetic polymorphism. The C677T polymorphism of the methylene-tetrahydrofolate reductase (MTHFR) gene is associated with a reduction of catalytic activity and is suggested to modify cancer risk differently depending on folate status. In this work the effect of folic acid deficiency on genome stability and radiosensitivity has been investigated in cultured lymphocytes of 12 subjects with different MTHFR genotype (four for each genotype). Cells were grown for 9 days with 12, 24 and 120 nM folic acid and analyzed in a comprehensive micronucleus test coupled with centromere characterization by CREST immunostaining. In other experiments, cells were grown with various folic acid concentrations, irradiated with 0.5 Gy of gamma rays and analyzed in the micronucleus test. The results obtained indicate that folic acid deficiency induces to a comparable extent chromosome loss and breakage, irrespective of the MTHFR genotype. The effect of folic acid was highly significant (P < 0.001) and explained >50% of variance of both types of micronuclei. Also nucleoplasmic bridges and buds were significantly increased under low folate supply; the increase in bridges was mainly observed in TT cells, highlighting a significant effect of the MTHFR genotype (P = 0.006) on this biomarker. Folic acid concentration significantly affected radiation-induced micronuclei (P < 0.001): the increased incidence of radiation-induced micronuclei with low folic acid was mainly accounted for by carriers of the variant MTHFR allele (both homozygotes and heterozygotes), but the overall effect of genotype did not attain statistical significance. Treatment with ionizing radiations also increased the frequency of nucleoplasmic bridges. The effect of folic acid level on this end-point was modulated by the MTHFR genotype (P for interaction = 0.02), with TT cells grown at low folic acid concentration apparently resistant to the induction of radiation-induced bridges. Finally, the effect of in vitro folate deprivation on global DNA methylation was evaluated in lymphocytes of six homozygous subjects (three CC and three TT). The results obtained suggest that, under the conditions of this work, folic acid deprivation is associated with global DNA hypermethylation.