Using neural network for simulations to improve the quality of disease diagnosis: Technical aspects

Mathematical models are important for the processes of cognition and decision-making. They provide a concise representation of significant relationships in the description of objects and situations. Adding new relationships leads to narrowing the scope of applicability of the model. The formula is an example of a compressed description of a potentially infinite set of objects and situations. Knowledge processing is based on the use of mathematical methods. In this case, it is the most thorough, at least from the point of view of strict logic and consistent formalization. To process knowledge, we must present it in some form that is convenient for analysis. Thus, when analyzing data and knowledge, we do not use them directly, but their representations. Mathematical models of objects and phenomena are an effective way of representation. This is now the most powerful method of cognition of processes, objects and phenomena. Modeling is a special way of scientific research. A mathematical model of an object is a mathematical structure interpreted within a given domain. © 2020, World Academy of Research in Science and Engineering. All rights reserved

Sentinel headache as a warning symptom of ischemic stroke

Background: There are no previous controlled studies of sentinel headache in ischemic stroke. The purpose of the present study was to evaluate the presence of such headache, its characteristics and possible risk factors as compared to a simultaneous control group. Methods: Eligible patients (n = 550) had first-ever acute ischemic stroke with presence of new infarction on magnetic resonance imaging with diffusion-weighted imaging (n = 469) or on computed tomography (n = 81). As a control group we studied in parallel patients (n = 192) who were admitted to the emergency room without acute neurological deficits or serious neurological or somatic disorders. Consecutive patients with stroke and a simultaneous control group were extensively interviewed soon after admission using validated neurologist conducted semi-structured interview forms. Based on our previous study of sentinel headache in transient ischemic attacks we defined sentinel headache as a new type of headache or a previous kind of headache with altered characteristics (severe intensity, increased frequency, absence of effect of drugs) within seven days before stroke. Results: Among 550 patients with stroke 94 patients (17.1%) had headache during seven days before stroke and 12 (6.2%) controls (p < 0.001; OR 3.9; 95% CI 1.7-5.8). Totally 81 patients (14.7%) had sentinel headache within the last week before stroke and one control. Attacks of arrythmia during seven days before stroke were significantly associated with sentinel headache (p = 0.04, OR 2.3; 95% CI 1.1-4.8). Conclusions: A new type of headache and a previous kind of headache with altered characteristics during one week before stroke are significantly more prevalent than in controls. These headaches represent sentinel headaches. Sudden onset of such headaches should alarm about stroke. © 2020 The Author(s)

The influence of bone substitute material on mechanical properties of trabecular bone in augmentation of intra-articular impression fractures. Experimental study

The purpose was to evaluate the effect of bone substitute materials on mechanical properties of trabecular bone adjacent to the joint. Material and methods A total of 21 female chinchilla rabbits weighing 3-3.5 kg was used for the experimental study. A bilateral impression fracture was simulated in the medial tibial condyle and surgically augmented with one of the bone substitution materials: beta-tricalcium phosphate, xenoplastic material and carbon nanostructures. The animals were sacrificed at 6, 12 and 24 weeks postsurgery. Uniaxial compression test was performed to determine mechanical properties of the tibial fragments. Bone microstructure was evaluated with scanning electron microscopy. Statistical data analysis was performed with nonparametric tests. Results Beta-tricalcium phosphate augmentation of the bone interface led to slow resorption accompanied by formation of adequate high-grade bone tissue with mechanical properties gradually increasing with greater observation time that indicated to the bone substitute integrated well with the host bone of the impression bone defect. Xenoplastic augmentation resulted in rapid resorption accompanied by formation of immature bone with mechanical properties declining at 6 to 12 weeks of observation. Carbon nanostructure augmentation of the bone interface caused perifocal bone resorption and absence of osteointegration with mechanical properties declining at 12 to 25 weeks of observation. © Gilev M.V., Zaytsev D.V., Izmodenova M.Y., Kiseleva D.V., Volokitina E.A., 2018

Analysis of the quality of diagnosis and treatment of primary headache in different social groups of the Ural Region

Objective: to analyze the quality of diagnosis and treatment of primary headache (HA) in different social groups of the Ural Region. Patients and methods. The study enrolled 3124 persons who were divided into three groups: 1) 1042 students; of them there were 719 women; mean age 20.6 years; range 17–40 years; 2) 1075 workers; of them there were 146 women; mean age 40.4 years; range 21–67 years; 3) 1007 blood donors; of them there were 484 women; mean age, 34.1 years; range 18–64 years. Semi-structured interviews involving the characteristics of HA and its prior diagnosis and treatment were conducted face-to-face in all those included in the study. HA was diagnosed using the International Classification of Headache Disorders, 3rd edition, beta version. Results and discussion. The following factors decreasing the quality of diagnosis and treatment of HA were identified in all the study groups: 1) low physician visit rates. Despite the high prevalence of all types of primary HA in 3 groups (67%), only 496 (23%) out of 2110 participants with HA visited their physician with this problem. Among the patients with HA, physicians were visited most often by 342 (35%) out of 968 students, least often by 60 (13%) out of 457 workers and by 94 (14%) out of 685 donors; 2) inadequate diagnosis of HA. Only 12 and 11.7% of the patients were correctly diagnosed with migraine and tension HA (THA), respectively; 3) the practically complete absence of preventive treatment for HA. The majority of patients used drugs to arrest HA attacks; preventive treatment for migraine was performed in 2 (0.4%) and not performed in any of the patients with THA. It is necessary to improve the diagnosis and treatment of primary HA and to elaborate new Russian clinical guidelines for patient management on the basis of international standards

Diagnostic Criteria for Acute Headache Attributed to Ischemic Stroke and for Sentinel Headache Before Ischemic Stroke

Background: Defining the relationship between a headache and stroke is essential. The current diagnostic criteria of the ICHD-3 for acute headache attributed to ischemic stroke are based primarily on the opinion of experts rather than on published clinical evidence based on extensive case-control studies in patients with first-ever stroke. Diagnostic criteria for sentinel headache before ischemic stroke do not exist. The present study aimed to develop explicit diagnostic criteria for headache attributed to ischemic stroke and for sentinel headache. Methods: This prospective case-control study included 550 patients (mean age 63.1, 54% males) with first-ever ischemic stroke and 192 control patients (mean age 58.7, 36% males) admitted to the emergency room without any acute neurological deficits or severe disorders. Standardized semi-structured interview forms were used to evaluate past and present headaches during face-to-face interviews by a neurologist on admission to the emergency room in both groups of patients. All headaches were diagnosed according to the ICHD-3. We tabulated the onset of different headaches before a first-ever ischemic stroke and at the time of onset of stroke. We divided them into three groups: a new type of headache, the previous headache with altered characteristics and previous unaltered headaches. The same was done for headaches in control patients within one week before admission to the hospital and at the time of entry. These data were used to create and test diagnostic criteria for acute headache attributed to stroke and sentinel headache. Results: Our previous studies showed that headache at onset of ischemic stroke was present in 82 (14.9%) of 550 patients, and 81 (14.7%) patients had sentinel headache within the last week before a stroke. Only 60% of the headaches at stroke onset fulfilled the diagnostic criteria of ICHD-3. Therefore, we proposed alternative criteria with a sensitivity of 100% and specificity of 97%. Besides, we developed diagnostic criteria for sentinel headache for the first time with a specificity of 98% and a sensitivity of 100%. Conclusions: We suggest alternative diagnostic criteria for acute headache attributed to ischemic stroke and new diagnostic criteria for sentinel headache with high sensitivity and specificity. © 2022, The Author(s)

Persistent headache after first-ever ischemic stroke: clinical characteristics and factors associated with its development

Background: It is poorly described how often headache attributed to stroke continues for more than 3 months, i.e. fulfils the criteria for persistent headache attributed to ischemic stroke. Our aims were: 1) to determine the incidence of persistent headache attributed to past first-ever ischemic stroke (International headache society categories 6.1.1.2); 2) to describe their characteristics and acute treatment; 3) to analyse the prevalence of medication overuse headache in patients with persistent headache after stroke; 4) to evaluate factors associated with the development of persistent headache after stroke. Methods: The study population consisted of 550 patients (mean age 63.1, 54% males) with first-ever ischemic stroke, among them 529 patients were followed up at least three months after stroke. Standardized semi-structured interview forms were used to evaluate these headaches during professional face-to-face interviews at stroke onset and telephone interviews at 3 months. Results: At three months, 61 patients (30 women and 31 men, the mean age 60.0) of 529 (11.5%) follow-up patients had a headache after stroke: 34 had a new type of headache, 21 had a headache with altered characteristics and 6 patients had a headache without any changes. Therefore 55 (10.4%) patients had a persistent headache attributed to ischemic stroke. Their clinical features included: less severity of accompanying symptoms, slowly decreasing frequency and development of medication overuse headache in one-third of the patients. The following factors were associated with these headaches: lack of sleep (29.1%, p = 0.009; OR 2.3; 95% CI 1.2–4.3), infarct in cerebellum (18.2%, p = 0.003; OR 3.0; 95% CI 1.4–6.6), stroke of undetermined etiology (50.9%, p = 0.003; OR 2.3; 95% CI 1.3–4.1), less than 8 points by NIHSS score (90.9%, p = 0.007; OR 3.4; 95% CI 1.4–8.6) and low prevalence of large-artery atherosclerosis (12.7%, p = 0.006; OR 0.3; 95% CI 0.2–0.80). Conclusion: Persistent headache attributed to ischemic stroke is not rare and frequently leads to medication overuse. The problem is often neglected because of other serious consequences of stroke but actually, it has a considerable impact on quality of life. It should be a focus of interest in the follow-up of stroke patients. © 2022, The Author(s).We thank Tatiana S. Tsypushkina and Polina A. Philimonova for the help with data collection. None

Association of vascular endothelial growth factor B (VEGFВ) gene polymorphisms with intracranial aneurysms

Intracranial aneurysm (IA) is a complex disease resulting in subarachnoid hemorrhage (SAH) due to a rupture. The average worldwide prevalence of this disease is about 2–5 %, with 50 % of them ending in death or neurological disorders of varying severity, with a high probability of recurrence of hemorrhage during the frst half of the year after rupture. Subarachnoid hemorrhage is annually registered in at least 18 thousand people in Russia. Associations of polymorphic variants rs594942 and rs11603042 of the VEGFB gene in intracranial aneurysm development in the Volga-Ural region of the Russian Federation with the presence of the symptom complex of undifferentiated connective tissue dysplasia (uDST) and arterial hypertension (AH) were investigated. The C* allele rs594942 and rs11603042 of the VEGFB gene is a marker of an increased risk of IA as a whole (p = 0.025; χ2 = 5.052; OR = 1.32) in women as a whole (p = 0.001; χ2 = 10.124; OR = 1.70) and in comorbid state with uDCT (p = 0.002; χ2 = 9.501; OR = 2.34) and AG (p = 0.006; χ2 = 7.385; OR = 2.109). We found that the genotype *C*C of locus rs594942 of the VEGFB gene is a marker of an increased risk of intracranial aneurysm in general (p = 0.017; χ2 = 5.702; OR = 1.49) and among women in general (p = 0.0005; χ2 = 12.078; OR = 2.25) and with the symptomatic complex uCTD (p = 0.007; χ2 = 7.173; OR = 2.67) and AH (p = 0.010; χ2 = 6.471; OR = 2.51). We have obtained new results on the role of polymorphic variants of the VEGFB gene in the formation of intracranial aneurysm, taking into account the presence of the symptom complex uDCT and AH among the residents of the Volga-Ural region of Russia. A burdened comorbid background and the presence of undifferentiated connective tissue dysplasia and arterial hypertension can contribute to an increased risk of intracranial aneurysm, as evidenced by the results of our study

Surgical treatment of intraarticular fractures using biocomposite application on the basis of b-threecalciumphosphate

The analysis of surgical treatment of 37 patients with intra articulate impression fractures of bones with use osteoplasty by a biocomposite on the basis of b-threecalciumphosphate is carried out. Expeditious treatment consisted in an open reduction and internal stabilization by plates; the area of impression defect was filled with a biocomposite on the basis of b-threecalciumphosphate. At all patients excellent and good results are received.Проведен анализ хирургического лечения 37 больных с внутрисуставными импрессионными переломами костей конечностей с применением костной пластики биокомпозитом на основе b-трикальцийфосфата. Оперативное лечение заключалось в открытой репозиции и стабилизации перелома накостными металлофиксаторами; область импрессионного дефекта элевировалась и заполнялась биокомпозитом на основе b-трикальцийфосфата. У всех больных получены отличные и хорошие результаты