Extra- and intracerebral course of the recurrent artery of Heubner

Background: The aim of the current study was to analyse the extra- and intracerebral course of the recurrent artery of Heubner (RAH) to provide detailed information for neurosurgeons operating in this area.Materials and methods: The material for this study was obtained from cadavers (ages 31–75 years) during routine autopsies. A total of 70 human brains (39 male and 31 female) were examined. The material was collected not later than 48 h post-mortem. People who died due to neurological disorders were not includedinto the study. Right after dissection the arteries were perfused with either acrylicpaint emulsion, polyvinyl chloride or Mercox CL-2R resin, through the Circle ofWillis or electively through the RAH. The obtained material was analysed usinga stereoscopic light microscope, magnification 2–40´.Results: The RAH was present in 138 hemispheres with a mean of 1.99 RAH per hemisphere (275 RAH in total). The mean RAH length was 25.2 mm and the mean RAH diameter, in its place of origin, was 1 mm. In 168 (61%) cases the RAH ran superiorly, in 88 (32%) cases anteriorly, in 11 (4%) cases inferiorly and in 8 (3%) cases posteriorlyto the A1 segment. In 70.2% of the cases the course of the RAH was parallel to theanterior communicating artery A1 segment, and in 29.8% of the cases the RAH archedtowards the olfactory tract. As the extracerebral course of the RAH was always tortuous,its length was 1 to 5 times the distance between its place of origin and the most lateralpoint of anterior perforated substance (APS) penetration. The intracerebral course ofthe RAH was almost always univectorial — towards the head of the caudate nucleus.The course of RAH branches depended on their number. When the number of RAH sand their branches was low, they separated immediately after penetrating the APS andformed multiple small branches. When the number of RAHs and branches was high,post-APS branching was less frequent and occurred in distal segments.Conclusions: The origin and course of the RAH is highly variable. The RAH, in itsextra- and intracerebral course, may join with the middle group of the lenticulostriatearteries or directly with the middle cerebral artery. This artery should beroutinely identified during anterior communicating artery aneurysm clipping toprevent postoperative neurological deficits

Mapping Tumor Spheroid Mechanics in Dependence of 3D Microenvironment Stiffness and Degradability by Brillouin Microscopy

Altered biophysical properties of cancer cells and of their microenvironment contribute to cancer progression. While the relationship between microenvironmental stiffness and cancer cell mechanical properties and responses has been previously studied using two-dimensional (2D) systems, much less is known about it in a physiologically more relevant 3D context and in particular for multicellular systems. To investigate the influence of microenvironment stiffness on tumor spheroid mechanics, we first generated MCF-7 tumor spheroids within matrix metalloproteinase (MMP)-degradable 3D polyethylene glycol (PEG)-heparin hydrogels, where spheroids showed reduced growth in stiffer hydrogels. We then quantitatively mapped the mechanical properties of tumor spheroids in situ using Brillouin microscopy. Maps acquired for tumor spheroids grown within stiff hydrogels showed elevated Brillouin frequency shifts (hence increased longitudinal elastic moduli) with increasing hydrogel stiffness. Maps furthermore revealed spatial variations of the mechanical properties across the spheroids’ cross-sections. When hydrogel degradability was blocked, comparable Brillouin frequency shifts of the MCF-7 spheroids were found in both compliant and stiff hydrogels, along with similar levels of growth-induced compressive stress. Under low compressive stress, single cells or free multicellular aggregates showed consistently lower Brillouin frequency shifts compared to spheroids growing within hydrogels. Thus, the spheroids’ mechanical properties were modulated by matrix stiffness and degradability as well as multicellularity, and also to the associated level of compressive stress felt by tumor spheroids. Spheroids generated from a panel of invasive breast, prostate and pancreatic cancer cell lines within degradable stiff hydrogels, showed higher Brillouin frequency shifts and less cell invasion compared to those in compliant hydrogels. Taken together, our findings contribute to a better understanding of the interplay between cancer cells and microenvironment mechanics and degradability, which is relevant to better understand cancer progression

The effects of pesticide mixtures on degradation of pendimethalin in soils

Most agronomic situations involve a sequence of herbicide, fungicide, and insecticide application. On the other hand, use of pesticidal combinations has become a standard practice in the production of many agricultural crops. One of the most important processes influencing the behavior of a pesticide in the environment is its degradation in soil. It is known that due to several pesticide applications in one vegetation season, the pesticide may be present in mixtures with other pesticides or xenobiotics in soil. This study examines the role which a mixture of chemicals plays in pesticide degradation. The influence of other pesticides on the rate of pendimethalin (PDM) degradation in soil was measured in controlled conditions. Mixtures of PDM with mancozeb or mancozeb and thiamethoxam significantly influenced the degradation of pendimethalin under controlled conditions. The second type of mixtures, with metribuzin or thiamethoxam, did not affect the behavior of pendimethalin in soil. Also, we determined the influence of water content on the rate of pendimethalin degradation alone in two soils and compared it to the rate in three pesticide mixtures. We compared two equations to evaluate the predictors of the rate of herbicide dissipation in soil: the first-order kinetic and the non-linear empirical models. We used the non-linear empirical model assuming that the degradation rate of a herbicide in soil is proportional to the difference of the observed concentration of herbicide in soil at time and concentration of herbicide in the last day of measurement

Assessing fitness-to-practice of overseas-trained health practitioners by Australian registration & accreditation bodies

Assessment of fitness-to-practice of health professionals trained overseas and who wish to practice in Australia is undertaken by a range of organisations. These organisations conduct assessments using a range of methods. However there is very little published about how these organisations conduct their assessments. The purpose of the current paper is to investigate the methods of assessment used by these organisations and the issues associated with conducting these assessments

Preliminary studies on the tolerance of three forms of Salix viminalis L. to different NaCl concentrations added to the soil substratum

Wstępne badania dotyczące wpływu różnych stężeń NaCl dodawanych do podłoża glebowego na trzy formy Salix viminalis L. wykazały, że najbardziej tolerancyjną na największe stężenie NaCl (0,34 mol·dm⁻³) okazała się forma Jorr. Osiągnęła ona największy plon suchej masy pędów (różnice statystycznie istotne). Największą koncentrację chlorofilu a + b stwierdzono w wariancie z podlewaniem 0,17 mol NaCl·dm⁻³. Formy Jorr i Tora tworzyły grupę jednorodną pod względem największej zawartości barwników asymilacyjnych. Forma Jorr w warunkach zasolenia zgromadziła najwięcej jonów sodu i potasu w liściach a najmniej jonów wapnia. Charakteryzowała się też wysokim wskaźnikiem względnej zawartości wody w liściach. U formy Jorr obniżenie plonu suchej masy pędów, w warunkach najwyższego zasolenia (podlanie 0,34 mol·dm⁻³ stężeniem soli), było istotnie mniejsze niż u pozostałych form. Największą suchą masę wytworzyła forma Jorr, a najmniejszą forma Tora niezależnie od kombinacji.The preliminary studies showed that the cultivated Jorr form proved to be the most tolerant to the highest NaCl concentration added to the soil substrate. It gained the highest yield of dry matter (significant differences). The highest concentration of chlorophyll a + b was recorded in 0.17 mol NaCl·dm⁻³ variant. Jorr and Tora forms made a homogenous form group in respect to the highest content of assimilation pigments. Jorr form showed the greatest abilities for accumulation of sodium and potassium ions and the lowest for accumulation of calcium ions. It is also characterized by the highest relative water content (RWC). In the Jorr form the highest decrease of dry matter yield was obserwed at the highest salination level (0.34 mol NaCl·dm⁻³ solution added to the subgrade). The greatest yield of dry matter was produced by the Jorr form and the lowest by the Tora form despite the solution combination