New experimental model of acute aqueductal blockage in cats: effects on cerebrospinal fluid pressure and the size of brain ventricles

It is generally assumed that cerebrospinal fluid (CSF) is secreted in the brain ventricles, and so after an acute blockage of the aqueduct of Sylvius an increase in the ventricular CSF pressure and dilation of isolated ventricles may be expected. We have tested this hypothesis in cats. After blocking the aqueduct, we measured the CSF pressure in both isolated ventricles and the cisterna magna, and performed radiographic monitoring of the cross-sectional area of the lateral ventricle. The complete aqueductal blockage was achieved by implanting a plastic cannula into the aqueduct of Sylvius through a small tunnel in the vermis of the cerebellum in the chloralose-anesthetized cats. After the reconstitution of the occipital bone, the CSF pressure was measured in the isolated ventricles via a plastic cannula implanted in the aqueduct of Sylvius and in the cisterna magna via a stainless steel cannula. During the following 2 h, the CSF pressures in the isolated ventricles and cisterna magna were identical to those in control conditions. We also monitored the ventricular cross-sectional area by means of radiography for 2 h after the aqueductal blockage and failed to observe any significant changes. When mock CSF was infused into isolated ventricles to imitate the CSF secretion, the gradient of pressure between the ventricle and cisterna magna developed, and disappeared as soon as the infusion was terminated. However, when mock CSF was infused into the cisterna magna at various rates, the resulting increased subarachnoid CSF pressure was accurately transmitted across the brain parenchyma into the CSF of isolated ventricles. The lack of the increase in the CSF pressure and ventricular dilation during 2 h of aqueductal blockage suggests that aqueductal obstruction by itself does not lead to development of hypertensive acute hydrocephalus in cats

MICROPLASTICS ASSESSMENT IN THE KRKA RIVER ESTUARY SURFACE WATER

Microplastics (MPs), commonly defined as particles less than 5 mm, are a persistent ubiquitous anthropogenic contaminant that can be found in every environment, making it a global environmental, health, and socioeconomic problem. Due to their high surface area, MPs adsorb toxic pollutants that become bioavailable to organisms upon ingestion as they are often mistaken for food leading to biomagnification (Bule et al., 2020). The sampling area represents the lower part of the Krka River Estuary and is under direct anthropogenic influence from the city of Šibenik runoff waters, nautical and communal ports, city harbor, tourism, mariculture, and fishing. Estuaries and harbors have been recognized as hotspots and transfer pathways for MPs primarily because of the vicinity of the urban environment that emits contaminants from various sources (Miller et al., 2021). The main focus of this research was to determine MPs size, shape, color, surface area, and abundance in surface water using volume-reduced samples collected by a net. Laboratory protocol included sieving, wet peroxidation (H2O2), density separation (saturated NaCl solution), sonication, and filtration. Filter papers were then visually inspected for MPs. Image processing and measurements were carried out with ImageJ/Fiji open-source software

Mapping of marine litter on the seafloor using WASSP S3 multibeam echo sounder and Chasing M2 ROV

Marine litter is a growing threat to the marine environment. Mapping of marine litter is becoming increasingly important to detect its potential hotspots and prevent their spread. In this paper, the applicability of the multibeam echo sounder (MBES) WASSP S3 and remotely operated underwater vehicle (ROV) Chasing M2 was tested in the detection and mapping of marine litter on the seafloor within the wider area of the St. Ante Channel (Šibenik, Croatia). Also, the precision assessment of WASSP S3 was tested at different cruising speeds. Results have shown that Chasing M2 can be used effectively for the initial detection of marine debris in shallow waters. However, if the underwater navigation and positioning system and auxiliary measurement scales are not used, the ROV has limited capabilities in deriving morphometric parameters of marine litter on the seafloor. This was determined by comparing the 3D model of a tire which was derived using video photogrammetry captured with ROV and the 3D model of a tire which was produced using a hand-held 3D scanner. Furthermore, the results have shown the WASSP S3 is not suitable for identifying marine litter smaller than 1 m at depths up to 10 m. The MBES WASSP S3 can detect marine litter that has a minimum area of 100 * 100 cm and a height of around 40 cm at depths up to 10 m. The results pointed to the need for caution when choosing an adequate sensor to detect and map marine litter on the seafloor. In addition, MBES interval measurements have shown that WASSP S3 precision is in the centimeter range (<10 cm) at different cruising speeds. The obtained results have helped to establish the guidelines for the integrated use of MBES, ROV, and UAV in the detection of marine litter on the seafloor

Interactions between Type 1 Interferons and the Th17 Response in Tuberculosis: Lessons Learned from Autoimmune Diseases

textabstractThe classical paradigm of tuberculosis (TB) immunity, with a central protective role for Th1 responses and IFN-γ-stimulated cellular responses, has been challenged by unsatisfactory results of vaccine strategies aimed at enhancing Th1 immunity. Moreover, preclinical TB models have shown that increasing IFN-γ responses in the lungs is more damaging to the host than to the pathogen. Type 1 interferon signaling and altered Th17 responses have also been associated with active TB, but their functional roles in TB pathogenesis remain to be established. These two host responses have been studied in more detail in autoimmune diseases (AID) and show functional interactions that are of potential interest in TB immunity. In this review, we first identify the role of type 1 interferons and Th17 immunity in TB, followed by an overview of interactions between these responses observed in systemic AID. We discuss (i) the effects of GM-CSF-secreting Th17.1 cells and type 1 interferons on CCR2+ monocytes; (ii) convergence of IL-17 and type 1 interferon signaling on stimulating B-cell activating factor production and the central role of neutrophils in this process; and (iii) synergy between IL-17 and type 1 interferons in the generation and function of tertiary lymphoid structures and the associated follicular helper T-cell responses. Evaluation of these autoimmune-related pathways in TB pathogenesis provides a new perspective on recent developments in TB research

Transventricular and transpial absorption of cerebrospinal fluid into cerebral microvessels

It is generally accepted that volume of cerebrospinal fluid (CSF) is secreted in brain ventricles and flows to subarachnoid space to be absorbed into dural venous sinuses or/and into lymphatics via perineural sheats of cranial nerves. Since 99% of CSF volume is water, in experiments on cats 3H-water was slowly infused into lateral ventricle and found that it does not flow to subarachnoid space but that it is rapidly absorbed transventricularly into periventricular capillaries. When 3H-water was infused in cortical subarachnoid space, it was absorbed locally into cerebral capillaries via pia mater. On the contrary, when macromolecule 3H-inulin is applied in CSF it is very slowly eliminated in bloodstream, and, with time, is carried by systolic-diastolic pulsations and mixing of CSF bidirectionally along CSF system. Thus, CSF volume (water) is absorbed rapidly into adjacent cerebral capillaries while inulin is distributed bidirectionally due to its long residence time in CSF Previously, the macromolecules have been used to study CSF volume hydrodynamics and with this misconception of CSF physiology arose

Effect of head position on cerebrospinal fluid pressure in cats: comparison with artificial model

AIM: To demonstrate that changes in the cerebrospinal fluid (CSF) pressure in the cranial cavity and spinal canal after head elevation from the horizontal level occur primarily due to the biophysical characteristics of the CSF system, ie, distensibility of the spinal dura. ----- METHODS: Experiments in vivo were performed on cats and a new artificial model of the CSF system with dimensions similar to the CSF system in cats, consisting of non-distensible cranial and distensible spinal part. Measurements of the CSF pressure in the cranial and spinal spaces were performed in chloralose-anesthetized cats (n = 10) in the horizontal position on the base of a stereotaxic apparatus (reference zero point) and in the position in which the head was elevated to 5 cm and 10 cm above that horizontal position. Changes in the CSF pressure in the cranial and spinal part of the model were measured in the cranial part positioned in the same way as the head in cats (n = 5). ----- RESULTS: When the cat was in the horizontal position, the values of the CSF pressure in the cranial (11.9 ± 1.1 cm H2O) and spinal (11.8 ± 0.6 cm H2O) space were not significantly different. When the head was elevated 5 cm or 10 cm above the reference zero point, the CSF pressure in the cranium significantly decreased to 7.7 ± 0.6 cm H2O and 4.7 ± 0.7 cm H2O, respectively, while the CSF pressure in the spinal space significantly increased to 13.8 ± 0.7 cm H2O and 18.5 ± 1.6 cm H2O, respectively (P<0.001 for both). When the artificial CSF model was positioned in the horizontal level and its cranial part elevated by 5 cm and 10 cm, the changes in the pressure were the same as those in the cats when in the same hydrostatic position. ------ CONCLUSION: The new model of the CSF system used in our study faithfully mimicked the changes in the CSF pressure in cats during head elevation in relation to the body. Changes in the pressure in the model were not accompanied by the changes in fluid volume in the non-distensible cranial part of the model. Thus, it seems that the changes in the CSF pressure occur due to the biophysical characteristics of the CSF system rather than the displacement of the blood and CSF volumes from the cranium to the lower part of body

Dynamics of distribution of (3)H-inulin between the cerebrospinal fluid compartments

Since the distribution of substances between various cerebrospinal fluid (CSF) compartments is poorly understood, we studied (3)H-inulin distribution, over time, after its injection into cisterna magna (CM) or lateral ventricle (LV) or cisterna corporis callosi (CCC) in dogs. After the injection into CM (3)H-inulin was well distributed to cisterna basalis (CB), lumbar (LSS) and cortical (CSS) subarachnoid spaces and less distributed to LV. When injected in LV (3)H-inulin was well distributed to all CSF compartments. However, after injection into CCC (3)H-inulin was mostly localized in CCC and adjacent CSS, while its concentrations were much lower in CM and CB and very low in LSS and LV. Concentrations of (3)H-inulin in venous plasma of superior sagittal sinus and arterial plasma were very low and did not differ significantly, while its concentration in urine was very high. In (3)H-inulin distribution it seems that two simultaneous processes are relevant: a) the pulsation of CSF with to-and-fro displacement of CSF and its mixing, carrying (3)H-inulin in all directions, and b) the passage of (3)H-inulin from CSF into nervous parenchyma and its rapid distribution to a huge surface area of capillaries by vessels pulsations. (3)H-inulin then slowly diffuses across capillary walls into the bloodstream to be eliminated in the urine

Effect of Head Position on Cerebrospinal Fluid Pressure in Cats: Comparison with Artificial Model

Aim: To demonstrate that changes in the cerebrospinal fluid (CSF) pressure in the cranial cavity and spinal canal after head elevation from the horizontal level occur primarily due to the biophysical characteristics of the CSF system, ie, distensibility of the spinal dura. Methods: Experiments in vivo were performed on cats and a new artificial model of the CSF system with dimensions similar to the CSF system in cats, consisting of non-distensible cranial and distensible spinal part. Measurements of the CSF pressure in the cranial and spinal spaces were performed in chloralose-anesthetized cats (n = 10) in the horizontal position on the base of a stereotaxic apparatus (reference zero point) and in the position in which the head was elevated to 5 cm and 10 cm above that horizontal position. Changes in the CSF pressure in the cranial and spinal part of the model were measured in the cranial part positioned in the same way as the head in cats (n = 5). Results: When the cat was in the horizontal position, the values of the CSF pressure in the cranial (11.9 ± 1.1 cm H2O) and spinal (11.8 ± 0.6 cm H2O) space were not significantly different. When the head was elevated 5 cm or 10 cm above the reference zero point, the CSF pressure in the cranium significantly decreased to 7.7 ± 0.6 cm H2O and 4.7 ± 0.7 cm H2O, respectively, while the CSF pressure in the spinal space significantly increased to 13.8 ± 0.7 cm H2O and 18.5 ± 1.6 cm H2O, respectively (P<0.001 for both). When the artificial CSF model was positioned in the horizontal level and its cranial part elevated by 5 cm and 10 cm, the changes in the pressure were the same as those in the cats when in the same hydrostatic position. Conclusions: The new model of the CSF system used in our study faithfully mimicked the changes in the CSF pressure in cats during head elevation in relation to the body. Changes in the pressure in the model were not accompanied by the changes in fluid volume in the non-distensible cranial part of the model. Thus, it seems that the changes in the CSF pressure occur due to the biophysical characteristics of the CSF system rather than the displacement of the blood and CSF volumes from the cranium to the lower part of body

Asymmetric Ring Opening in Tetrazine‐based Ligand Affording a Tetranuclear Opto‐Magnetic Ytterbium Complex

We report the formation of a tetranuclear lanthanide cluster, [Yb 4 (bpzch) 2 (fod) 10 ] ( 1 ), which occurs from a serendipitous ring opening of the functionalized tetrazine bridging ligand, bpztz (3,6‐dipyrazin‐2‐yl‐1,2,4,5‐tetrazine) upon reacting with Yb(fod) 3 (fod ‐ = 6,6,7,7,8,8,8‐heptafluoro‐2,2‐dimethyl‐3,5‐octandionate). Compound 1 was structurally elucidated via single‐crystal X‐ray crystallography and subsequently magnetically and spectroscopically characterized to analyse its magnetisation dynamics and its luminescence behaviour. Computational studies validate the observed M J energy levels attained by spectroscopy and provides a clearer picture of the slow relaxation of the magnetisation dynamics and relaxation pathways. These studies demonstrate that 1 acts as a single‐molecule magnet (SMM) under an applied magnetic field in which the relaxation occurs via a combination of Raman, direct, and quantum tunnelling processes, a behaviour further rationalized analysing the luminescent properties. This marks the first lanthanide‐containing molecule that forms by means of an asymmetric tetrazine decomposition.peerReviewe

Towards Conservation Agriculture systems in Moldova

As the world population and food production demands rise, keeping agricultural soils and landscapes healthy and productive are of paramount importance to sustaining local and global food security and the flow of ecosystem services to society. The global population, expected to reach 9.7 billion people by 2050, will put additional pressure on the available land area and resources for agricultural production. Sustainable production intensification for food security is a major challenge to both industrialized and developing countries. The paper focuses on the results from long-term multi-factorial experiments involving tillage practices, crop rotations and fertilization to study the interactions amongst the treatments in the context of sustainable production intensification. The paper discusses the results in relation to reported performance of crops and soil quality in Conservation Agriculture systems that are based on no or minimum soil disturbance (no-till seeding and weeding), maintenance of soil mulch cover with crop biomass and cover crops, and diversified cropping s involving annuals and perennials. Conservation Agriculture also emphasizes the necessity of an agro-ecosystems approach to the management of agricultural land for sustainable production intensification, as well as to the site-specificity of agricultural production. Arguments in favor of avoiding the use of soil tillage are discussed together with agro-ecological principles for sustainable intensification of agriculture. More interdisciplinary systems research is required to support the transformation of agriculture from the conventional tillage agriculture to a more sustainable agriculture based on the principles and practices of Conservation Agriculture, along with other complementary practices of integrated crop, nutrient, water, pest, energy and farm power management