Goran Ćurić

Function of circle of Willis

Nearly 400 years ago, Thomas Willis described the arterial ring at the base of the brain (the circle of Willis, CW) and recognized it as a compensatory system in the case of arterial occlusion. This theory is still accepted. We present several arguments that via negativa should discard the compensatory theory. (1) Current theory is anthropocentric; it ignores other species and their analog structures. (2) Arterial pathologies are diseases of old age, appearing after gene propagation. (3) According to the current theory, evolution has foresight. (4) Its commonness among animals indicates that it is probably a convergent evolutionary structure. (5) It was observed that communicating arteries are too small for effective blood flow, and (6) missing or hypoplastic in the majority of the population. We infer that CW, under physiologic conditions, serves as a passive pressure dissipating system; without considerable blood flow, pressure is transferred from the high to low pressure end, the latter being another arterial component of CW. Pressure gradient exists because pulse wave and blood flow arrive into the skull through different cerebral arteries asynchronously, due to arterial tree asymmetry. Therefore, CW and its communicating arteries protect cerebral artery and blood–brain barrier from hemodynamic stress.

Population Substructure Can Significantly Affect Reliability of a DNA‐led Process of Identification of Mass Fatality Victims

Abstract:  Aiming to evaluate the effects of population substructure on the reliability of a DNA correspondence in the process of human identification, we used the model of “in silico” constructed populations with and without substructure. Effects of population substructure were evaluated at the level of locus heterozygosity, Hardy–Weinberg equilibrium and mini‐haplotype distribution. Inbreeding in a subpopulation of 100 individuals through 10 generations did not significantly alter the level of heterozygosity and Hardy–Weinberg equilibrium. However, analysis of mini‐haplotype distribution revealed a significant homogenization in separated subpopulations. Average observed mini‐haplotype frequency (fo) increased to threefold from expected values (fe), and the number of mini‐haplotypes with fo/fe above 10 increased over sixfold, suggesting that the effects of population substructure on calculated likelihood ratios (LR) might be larger than previously estimated. In most criminal cases, this would not represent a problem, whereas for identifications in large‐scale mass fatality events, population substructure might considerably increase the risk of false identification.

Analysis of biomechanical properties of patellar ligament graft and quadruple hamstring tendon graft

INTRODUCTION Two types of transplant are commonly used in the surgical management of anterior cruciate ligament lesions: the central part of the patellar ligament and quadruple tendons of the gracilis muscle and semitendinosus muscle. AIMS The aim of this study was to determine the biomechanical characteristics of patellar ligament transplants and transplants of the quadruple tendons of the hamstring muscles under tensile force in the laboratory, and to compare the results in each group of samples. MATERIALS AND METHODS The study comprised 160 specimens: 40 specimens of gracilis muscle tendons, 40 of semitendinosus muscle tendons, 40 of quadruple tendons and 40 of the patellar ligament, approximately equally distributed according to sex, age (50-70 years) and the side of the body from which the specimen had been taken. RESULTS The working curve analysis of the specimens under tensile load of a maximum force of 30N showed the least elongation (0.31%) in the quadruple tendon, followed by the gracilis muscle tendon (1.48%) and patellar ligament tendon (3.91%). CONCLUSIONS The quadruple tendon specimen showed greater strength and higher elasticity compared with the patellar ligament specimen, which proved the starting hypothesis.

Vertebral marrow adipose tissue adipokines as a possible cause of intervertebral disc inflammation

Joint Bone Spine - In Press.Proof corrected by the author Available online since mercredi 22 novembre 2017

Penetrating arteries of the cerebral white matter: The importance of vascular territories of delivering arteries and completeness of circle of Willis

Dear editor, We read with great interest the article by Ryan et al. They established association of incompleteness of the circle of Willis (CW) with higher incidence of white matter lesions (WML); lack of anterior communicating artery was associated with more WML in frontal region, while lack of posterior communicating artery with more WML in parieto-occipital region. However, we want to make minor criticism from the methodological point of view. Ryan et al. grouped WML by anatomical, not by supply regions; bifrontal area is supplied by anterior and middle cerebral artery (carotid branches), and parieto-occipital region by middle and posterior cerebral artery (branches of carotid and vertebral artery, respectively). In the light of our recent paper, we find that the distribution ofWML should have been presented according to exact territories of (I) internal carotid artery and vertebral artery, and/or (II) anterior cerebral artery, middle cerebral artery, and posterior cerebral artery. Furthermore, as a possible explanation of observed distribution of WML, the authors offered hypoperfusion, along with anatomical properties of the penetrating arteries. Suggested explanation is based on previous studies that found association of hypoperfusion and WML and, therefore, any causal relationship cannot be deduced. The white matter is supplied by penetrating arteries, tubular vessels without anastomotic connections. Penetrating arteries lack extrinsic control and are exposed to the highest pressure loads in the human body. Lack of communicating artery might further increase pressure load on penetrating arteries, causing barotrauma and consequent WML. Even hypoplastic arteries would represent a pressure valve—allowing transfer of pressure, when too narrow to enable significant blood flow. This is in line with results of Ryan et al.; patients with hypoplastic CW had similar WML score as patients with classical CW, where vessels transfer pressure and blood.

Epicardial Adipose Tissue Is Nonlinearly Related to Anthropometric Measures and Subcutaneous Adipose Tissue

Introduction. Adipose tissue is the largest endocrine organ, composed of subcutaneous (SAT) and visceral adipose tissue (VAT), the latter being highly associated with coronary artery disease (CAD). Expansion of epicardial adipose tissue (EAT) is linked to CAD. One way of assessing the CAD risk is with low-cost anthropometric measures, although they are inaccurate and cannot discriminate between VAT and SAT. The aim of this study is to evaluate (1) the relationship between EAT thickness, SAT thickness and anthropometric measures in a cohort of patients assessed at the cardiology unit and (2) determine predictive power of anthropometric measures and EAT and SAT thickness in establishment of CAD. Methods. Anthropometric measures were obtained from 53 CAD and 42 non-CAD patients. Vascular and structural statuses were obtained with coronarography and echocardiography, as well as measurements of the EAT and SAT thickness. Results. Anthropometric measures showed moderate positive correlation with EAT and SAT thickness. Anthropometric measures and SAT follow nonlinear S curve relationship with EAT. Strong nonlinear power curve relationship was observed between EAT and SAT thinner than 10 mm. Anthropometric measures and EAT and SAT were poor predictors of CAD. Conclusion. Anthropometric measures and SAT have nonlinear relationship with EAT. EAT thickness and anthropometric measures have similar CAD predictive value.