27 research outputs found
Partitioning into common independent sets via relaxing strongly base orderability
No full textThe problem of covering the ground set of two matroids by a minimum number of common independent sets is notoriously hard even in very restricted settings, i.e. when the goal is to decide if two common independent sets suffice or not. Nevertheless, as the problem generalizes several long-standing open questions, identifying tractable cases is of particular interest. Strongly base orderable matroids form a class for which a basis-exchange condition that is much stronger than the standard axiom is met. As a result, several problems that are open for arbitrary matroids can be solved for this class. In particular, Davies and McDiarmid showed that if both matroids are strongly base orderable, then the covering number of their intersection coincides with the maximum of their covering numbers.Motivated by their result, we propose relaxations of strongly base orderability in two directions. First we weaken the basis exchange condition, which leads to the definition of a new, complete class of matroids with distinguished algorithmic properties. Second, we introduce the notion of covering the circuits of a matroid by a graph, and consider the cases when the graph is (A) 2-regular, or (B) a path. We give an extensive list of results explaining how the proposed relaxations compare to existing conjectures and theorems on coverings by common independent sets.(c) 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons .org /licenses /by -nc -nd /4 .0/)
Genetic and environmental influence on thyroid gland volume and thickness of thyroid isthmus: a twin study
No full textABSTRACT Objectives: Decreased thyroid volume has been related to increased prevalence of thyroid cancer. Subjects and methods: One hundred and fourteen Hungarian adult twin pairs (69 monozygotic, 45 dizygotic) with or without known thyroid disorders underwent thyroid ultrasound. Thickness of the thyroid isthmus was measured at the thickest portion of the gland in the midline using electronic calipers at the time of scanning. Volume of the thyroid lobe was computed according to the following formula: thyroid height*width*depth*correction factor (0.63). Results: Age-, sex-, body mass indexand smoking-adjusted heritability of the thickness of thyroid isthmus was 50% (95% confidence interval [CI], 35 to 66%). Neither left nor right thyroid volume showed additive genetic effects, but shared environments were 68% (95% CI, 48 to 80%) and 79% (95% CI, 72 to 87%), respectively. Magnitudes of monozygotic and dizygotic co-twin correlations were not substantially impacted by the correction of covariates of body mass index and smoking. Unshared environmental effects showed a moderate influence on dependent parameters (24-50%). Conclusions: Our analysis support that familial factors are important for thyroid measures in a general twin population. A larger sample size is needed to show whether this is because of common environmental (e.g. intrauterine effects, regional nutrition habits, iodine supply) or genetic effects
Absent right common carotid artery with stenting of symptomatic internal carotid artery stenosis
No full textAbsent common carotid artery with independent origin of internal and external carotid arteries from the subclavian artery is a rare but recognized phenomenon. We describe one such case with an associated symptomatic proximal high-grade stenosis of the right internal carotid artery. The abnormal carotid anatomy was not initially well appreciated, resulting in a failed surgical exploration and subsequent successful endovascular carotid stenting. To our knowledge, this is the first reported case of carotid stent in a right internal carotid artery originating from the subclavian artery
Genetic and environmental influence on thyroid gland volume and thickness of thyroid isthmus: a twin study
No full textABSTRACT Objectives: Decreased thyroid volume has been related to increased prevalence of thyroid cancer. Subjects and methods: One hundred and fourteen Hungarian adult twin pairs (69 monozygotic, 45 dizygotic) with or without known thyroid disorders underwent thyroid ultrasound. Thickness of the thyroid isthmus was measured at the thickest portion of the gland in the midline using electronic calipers at the time of scanning. Volume of the thyroid lobe was computed according to the following formula: thyroid height*width*depth*correction factor (0.63). Results: Age-, sex-, body mass indexand smoking-adjusted heritability of the thickness of thyroid isthmus was 50% (95% confidence interval [CI], 35 to 66%). Neither left nor right thyroid volume showed additive genetic effects, but shared environments were 68% (95% CI, 48 to 80%) and 79% (95% CI, 72 to 87%), respectively. Magnitudes of monozygotic and dizygotic co-twin correlations were not substantially impacted by the correction of covariates of body mass index and smoking. Unshared environmental effects showed a moderate influence on dependent parameters (24-50%). Conclusions: Our analysis support that familial factors are important for thyroid measures in a general twin population. A larger sample size is needed to show whether this is because of common environmental (e.g. intrauterine effects, regional nutrition habits, iodine supply) or genetic effects. Arch Endocrinol Metab. 2015;59(6):487-9
Digital Slide and Virtual Microscopy-Based Routine and Telepathology Evaluation of Gastrointestinal Biopsy Specimen
No full textGenetic and environmental variance of renal parenchymal thickness: a twin study
No full textAim To estimate heritability and environmental effects on
renal parenchymal thickness.
Methods In this twin study, renal parenchymal thickness
of 98 Hungarian healthy adult twin pairs (68 monozygotic,
30 dizygotic) without kidney disease was measured bilaterally
using renal ultrasound with Esaote MyLab 70X ultrasound
machine with low-frequency curved transducers
(1-8 MHz).
Results In both monozygotic and dizygotic group there
were more women (76.5%). Mean right and left renal parenchymal
thickness was 1.32 ± 0.33 cm and 1.62 ± 0.31
cm, respectively. Age- and sex-adjusted heritability of renal
parenchymal thickness was 0.0% (95% confidence interval,
0.0 to 50.2%), shared and unshared environmental
factor was 30.2% (4.1 to 55.9%) and 69.8% (45.8 to 89.5%),
respectively.
Conclusion This study shows a negligible role of heritability
and an important role of environmental effects in developing
renal parenchymal thickness, emphasizing the importance
of lifestyle for primary prevention
Heritability of central blood pressure and arterial stiffness: a twin study
No full textOBJECTIVE:: Central blood pressure and aortic stiffness have been consistently reported as strong cardiovascular risk factors. Twin studies by comparing identical with nonidentical twins produce information on the relative contribution of genes and environment. METHODS:: One hundred and fifty-four monozygotic (MZ) and 42 dizygotic (DZ) twin pairs (age 43 +/- 17 years) from Hungary and the United States underwent brachial and central augmentation index (AIx), brachial and central pressure, and aortic pulse wave velocity (PWV) measurements with the invasively validated Arteriograph device. Bivariate Cholesky decomposition models were applied. RESULTS:: Age-adjusted, sex-adjusted and country-adjusted heritability was 60.0% for central SBP [95% confidence interval (CI), 44.8-69.6%], 50.1% for aortic PWV (95%CI, 26.0-66.8%), 48.7% for aortic AIx (95%CI, 1.7-74.0%), 46.8% for brachial AIx (95%CI, 1.1-73.8%), 46.7% for central pulse pressure (PP) (95%CI, 12.4-61.4%), and 30.0% for brachial PP (95%CI, 0.0-53.4%). Central SBP and PP had strong bivariate correlations with brachial (r = 0.461 and 0.425) and central AIx (r = 0.457 and 0.419), as well as with aortic PWV (r = 0.341 and 0.292, all P < 0.001). Brachial PP had a weak correlation with brachial AIx (r = -0.118, P < 0.05), central AIx (r = -0.122, P < 0.05), and none with aortic PWV (r = 0.08, P = n.s.). Genetic factors explained a moderate phenotypic correlation between central PP, SBP, brachial SBP and aortic PWV. CONCLUSIONS:: Central systolic and PPs, brachial PP, AIx, aortic PWV are moderately heritable. A moderate genetic covariance among aortic PWV and central PP, central SBP and brachial SBP was found
P121 Background of the Development of Carotid and Femoral Atherosclerotic Plaques in Twins
No full textAbstract Introduction Development of carotid and femoral atherosclerotic plaques proved to be heritable in previous studies. However, no comprehensive ultrasonographic evaluation of the volume and types of plaque has been performed. Methods Comprehensive carotid and femoral arterial ultrasound examination (Samsung RS85, arterial analysis, 15 MHz probe) was performed in 92 Hungarian twins (54 monozygotic, MZ and 38 dizygotic, DZ twin pairs, mean age 54 ± 13 years). The volume of plaques was automatically measured, and the plaque type was grouped according to echogenicity. Raw heritability was evaluated using the Falconer formula. Results No heritability of the total number of carotid and femoral plaques and total plaque volume was detected. Although the number of carotid plaques themselves has been found to be hereditary (h2 = 0.492), the volume of carotid and femoral plaques as well as the number of femoral plaques were not heritable. More MZ twin pairs were discordant in the presence of soft plaques in the carotid artery as DZ twin pairs, but greater similarity in femoral plaques was not detected between MZ twins, which does not indicate a genetic background. The presence of calcified and mixed echogenic carotid plaques in the MZ twins was more concordant as in DZ twins, indicating inheritance. Conclusion The total number and volume of carotid and femoral plaques are influenced by the environment. Different plaque types have different backgrounds: while calcified and mixed echogenic carotid plaques are more affected by genetics, soft carotid and femoral plaques are more affected by the environment
Timing and frequency of complications after carotid artery stenting: what is the optimal period of observation?
No full textAbstractObjectiveCurrently our standard of practice is that patients undergoing carotid artery stenting (CAS) may be safely discharged on the first day post-procedure. However, many patients are completely independent on the evening of procedure. Therefore we sought to establish the safety and feasibility of same-day discharge by assessing frequency and time of complications in the first 30 days after CAS.MethodCase records for 208 consecutive patients who had undergone CAS from October 1999 to October 2002 were retrospectively reviewed. Excluded were four cases in which combined CAS and carotid endarterectomy was performed to treat synchronous stenosis. Of the remaining 204 cases, involving 201 patients (three patients underwent staged bilateral CAS), 173 (84.8%) were symptomatic and 31 (15.2%) were asymptomatic.ResultThirty-eight major events or death (inclusive of all neurologic events and any complications that required treatment) were recorded in the first 30 days after CAS, for an event rate of 18.6% per case. These were 7 (3.4%) major access site complications; 18 (8.8%) neurologic events, of which 10 (4.9%) were transient ischemic events and 8 (3.9%) were strokes (including minor, major, and fatal stroke); 8 (3.9%) cardiovascular complications; and five (2.5%) other events. Twenty (52.6%) events occurred in the first 6 hours after CAS, 2 (5.3%) between 6 and 12 hours, 3 (7.9%) between 12 and 24 hours, and 13 (34.2%) 24 hours to 30 days post procedure. Four (2.0%) deaths were recorded in this period, 1 secondary to stroke, 1 from a perforated myocardium from a temporary pacing wire, and 2 from unrelated causes. The 30-days stroke and death rate was 5.4% (11 of 204 patients).ConclusionTime of complications suggests that outpatient performance of CAS is feasible and safe in selected patients
Preoperative uterine artery embolisation before hysterectomy in women with giant uterine fibroid and HIV-associated nephropathy
No full textUterine fibroids are the most common pelvic benign tumours occurring in women of reproductive age. Current treatment options include surgical procedures, pharmacological therapies, and minimally invasive procedures. The most commonly applied and accepted minimally invasive procedure used in the treatment of symptomatic uterine fibroid is uterine artery embolisation (UAE). Uterine artery embolisation is a minimally invasive procedure that can be used either as an auxiliary method or the main treatment method of symptomatic uterine fibroids. We would like to present the application of pre-operative UAE before hysterectomy in anaemic women with giant uterine fibroid (21.9 × 14.9 × 10.4 cm) and HIV-associated nephropathy. Among the possible treatment options for uterine fibroids in cases like the one presented in our manuscript, hysterectomy is the treatment of choice. However, surgical treatment in a patient with severe comorbid conditions and giant uterine fibroid carries serious risk of perioperative complications. Pre-operative UAE decreases such risk by reducing blood loss during hysterectomy and shortening operation/anaesthesia time. Although the benefits of pre-operative UAE before planned myomectomy or hysterectomy in high surgical risk patients with large fibroids has yet to be confirmed in a well-designed clinical trial, this procedure seems to be a promising tool to reduce the risk of perioperative complications in such patients
