Network Constraints on Longitudinal Grey Matter Changes in First Episode Psychosis

Background: Different regions of the brain's grey matter are connected by a complex structural network of white matter fibres which are responsible for the propagation of action potentials and the transport of trophic and other molecules. In neurodegenerative disease, these connections constrain the way in which grey matter volume loss progresses. Here, we investigated whether connectome architecture also shapes the spatial pattern of longitudinal grey matter volume changes attributable to illness and antipsychotic medication in first episode psychosis (FEP). Methods: We conducted a triple-blind randomised placebo-control MRI study where 62 young adults with first episode psychosis received either an atypical antipsychotic or placebo over 6-months. A healthy control group was also recruited. Anatomical MRI scans were acquired at baseline, 3-months and 12-months. Deformation-based morphometry was used to estimate illness-related and antipsychotic-related grey matter volume changes over time. Representative functional and structural brain connectivity patterns were derived from an independent healthy control group using resting-state functional MRI and diffusion-weighted imaging. We used neighbourhood deformation models to predict the extent of brain change in a given area by the changes observed in areas to which it is either structurally connected or functionally coupled. Results: At baseline, we found that empirical illness-related regional volume differences were strongly correlated with predicted differences using a model constrained by structural connectivity weights (ρ = .541; p < .001). At 3-months and 12-months, we also found a strong correlation between longitudinal regional illness-related (ρ > .516; p < .001) and antipsychotic-related volume change (ρ > .591; p < .001) with volumetric changes in structurally connected areas. These correlations were significantly greater than those observed across various null models accounting for lower-order spatial and network properties of the data. Associations between empirical and predicted volume change estimates were much lower for models that only considered binary structural connectivity (all ρ < .376), or which were constrained by inter-regional functional coupling (all ρ < .436). Finally, we found that potential epicentres of volume change emerged posteriorly early in the illness and shifted to the prefrontal cortex by later illness stages. Conclusion: Psychosis- and antipsychotic-related grey matter volume changes are strongly shaped by anatomical brain connectivity. This result is consistent with findings in other neurological disorders and implies that such connections may constrain pathological processes causing brain dysfunction in FEP.

Disassembly and Mislocalization of AQP4 in Incipient Scar Formation After Experimental Stroke

There is an urgent need to better understand the mechanisms involved in scar formation in brain. It is well known that astrocytes are critically engaged in this process. Here we analyze in-cipient scar formation one week after a discrete ischemic insult to the cerebral cortex. We show that the infarct border zone is characterized by pronounced changes in the organization and subcellular localization of the major astrocytic protein AQP4. Specifically there is a loss of AQP4 from astrocytic endfoot membranes that anchor astrocytes to pericapillary basal laminae and a disassembly of the supramolecular AQP4 complexes that normally abound in these membranes. This disassembly may be mechanistically coupled to a downregulation of the newly discovered AQP4 isoform AQP4ex. AQP4 has adhesive properties and is assumed to facilitate astrocyte mo-bility by permitting rapid volume changes at the leading edges of migrating astrocytes. Thus, the present findings provide new insight in the molecular basis of incipient scar formation.

Liposuction in cancer-related lower extremity lymphedema: an investigative study on clinical applications

Background Lymphedema is a progressive, noncurable condition consisting of increases in subcutaneous fat and interstitial fluid in the limbs and fibrosis during later stages. The disease most commonly affects the limbs following injury to or removal of the lymph nodes. The aim of this study was to investigate the therapeutic outcomes of liposuction for cancer-related lower extremity lymphedema. Methods Sixty-two patients with cancer-related lymphedema in the unilateral lower extremity were recruited for this study, and all patients underwent liposuction. The volume of hemorrhage and lipids, the operation time, and the volume changes of the affected extremity were compared by applying the t tests, and the subjective feelings of patients were compared with the chi-square tests. Results The total lipid volume was 2539 ± 1253.5 ml, and the hemorrhage volume was 828 ± 311.8 ml. For the comparison of objective indices, (1) the percent volume differences (PVDs) before surgery, intraoperatively, and at the 3-month follow-up were 5.5 ± 12.2 vs. 11.6 ± 18.4 vs. 43.2 ± 23.7, P < 0.05, respectively; (2) greater lipid volumes and higher liposuction rates were observed for female patients, as was a smaller volume of hemorrhage; (3) greater hemorrhage volumes were observed in patients with a history of recurrent erysipelas; and (4) greater lipid volumes and liposuction rates (LRs) and smaller hemorrhage volumes were observed for stage II than for stage III patients. Conclusions Liposuction is an effective therapy for cancer-related lower extremity lymphedema. Sex, stage, and recurrent erysipelas history influence the course and effect of liposuction.

Rational design of zwitterionic porous organic framework loading Co (II) ions to host sulfur and synergistically boost polysulfides redox kinetics for lithium sulfur batteries

In the development of lithium-sulfur batteries (LiSBs), the irreversible volume changes, annoying shuttle effect and slow conversion kinetics of lithium polysulfides (LiPSs) are main obstacles for further commercialization. Therefore, a...

Comparison of Packed Cell Volume Changes after Erythropoietin Administration and Blood Transfusion in Patients with Anemia of Chronic Kidney Disease on Hemodialysis

Introduction: Anemia of chronic kidney disease (CKD) can be managed by regular administration of erythropoiesis stimulating agents (ESAs) and/or blood transfusion. The response to these therapies can be monitored by serial packed cell volume (PCV). Objective: This study was done to compare the temporal changes in PCV after ESA therapy and blood transfusion in patients with recently diagnosed anemia in CKD stage 5 on hemodialysis (CKD 5 HD). Methods: Medical records of patients undergoing hemodialysis at the National Kidney Center, Balaju, Kathmandu from July to September 2013 were examined retrospectively. The data collected were analyzed using Minitab 16. Results: A total of 44 patients were on ESA therapy while 48 patients were on blood transfusion. The mean PCV at the start of blood transfusion was significantly lower than the mean PCV at the start of ESA therapy (p = 0.000) but at four weeks, the mean PCV in blood transfusion group was significantly greater than that in ESA therapy group (p = 0.008). At eight weeks and twelve weeks, the mean PCVs in both groups were not significantly different from each other (p = 0.949 and p = 0.747). Conclusions: Blood transfusion increases PCV immediately and in sustained manner while with ESA therapy, the response takes a longer time to manifest. A large number of non-responders to ESA therapy may have influenced the findings of this study. It is recommended that adequate dosing of ESA and attention to comorbid conditions be followed during ESA therapy. Keywords: Anemia; chronic renal insufficiency; blood transfusion; hematinics.

Dilatometry of Steel for the Production of 5.56 mm Calibre Rifle Barrels

During high rates of fire, the bore of the firearm barrel is exposed to high temperatures. This exposure induces structural changes in the barrel material, which is especially significant for the substrate of the galvanic chrome plating. The alloy steel grades used currently for firearm barrels, when exposed to heating above the ferrite stability limits, develop a phase transition with a discrete negative change in the material volume, which results in typical crazing in the bore. This effect is destructive to the galvanic chrome plating, leading to a loss of adhesion, which reduces the ballistic performance of the firearm, especially its muzzle velocity. This can be prevented by manufacturing barrels from steels having a limited range of phase transitions. The primary method for determining the presence of distinct volume changes in steel due to phase transition is dilatometry over a wide temperature range, which includes the interval within which the barrel bore is heated. This paper presents the dilatometry results for four steel grades, which included a steel grade currently used for firearm barrels, and an analysis of the effects of phase transition on the degradation of the barrel bore.

Treatment-Specific Hippocampal Subfield Volume Changes With Antidepressant Medication or Cognitive-Behavior Therapy in Treatment-Naive Depression

Background: Hippocampal atrophy has been consistently reported in major depressive disorder with more recent focus on subfields. However, literature on hippocampal volume changes after antidepressant treatment has been limited. The first-line treatments for depression include antidepressant medication (ADM) or cognitive-behavior therapy (CBT). To understand the differential effects of CBT and ADM on the hippocampus, we investigated the volume alterations of hippocampal subfields with treatment, outcome, and chronicity in treatment-naïve depression patients.Methods: Treatment-naïve depressed patients from the PReDICT study were included in this analysis. A total of 172 patients who completed 12 weeks of randomized treatment with CBT (n = 45) or ADM (n = 127) were included for hippocampal subfield volume analysis. Forty healthy controls were also included for the baseline comparison. Freesurfer 6.0 was used to segment 26 hippocampal substructures and bilateral whole hippocampus from baseline and week 12 structural MRI scans. A generalized linear model with covariates of age and gender was used for group statistical tests. A linear mixed model for the repeated measures with covariates of age and gender was used to examine volumetric changes over time and the contributing effects of treatment type, outcome, and illness chronicity.Results: Of the 172 patients, 85 achieved remission (63/127 ADM, 22/45 CBT). MDD patients showed smaller baseline volumes than healthy controls in CA1, CA3, CA4, parasubiculum, GC-ML-DG, Hippocampal Amygdala Transition Area (HATA), and fimbria. Over 12 weeks of treatment, further declines in the volumes of CA1, fimbria, subiculum, and HATA were observed regardless of treatment type or outcome. CBT remitters, but not ADM remitters, showed volume reduction in the right hippocampal tail. Unlike ADM remitters, ADM non-responders had a decline in volume in the bilateral hippocampal tails. Baseline volume of left presubiculum (regardless of treatment type) and right fimbria and HATA in CBT patients were correlated with a continuous measure of clinical improvement. Chronicity of depression had no effect on any measures of hippocampal subfield volumes.Conclusion: Two first-line antidepressant treatments, CBT and ADM, have different effects on hippocampal tail after 12 weeks. This finding suggests that remission achieved via ADM may protect against progressive hippocampal atrophy by altering neuronal plasticity or supporting neurogenesis. Studies with multimodal neuroimaging, including functional and structural analysis, are needed to assess further the impact of two different antidepressant treatments on hippocampal subfields.

External factors that affect the photoplethysmography waveforms

Photoplethysmography (PPG) is a simple and inexpensive technology used in many smart devices to monitor cardiovascular health. The PPG sensors use LED lights to penetrate into the bloodstream to detect the different blood volume changes in the tissue through skin contact by sensing the amount of light that hits the sensor. Typically, the data are displayed on a graph and it forms the pulse waveform. The information from the produced pulse waveform can be useful in calculating measurements that help monitor cardiovascular health, such as blood pressure. With many more people beginning to monitor their health status on their smart devices, it is extremely important that the PPG signal is accurate. Designing a simple experiment with standard laboratory equipment and commercial sensors, we wanted to find how external factors influence the results. In this study, it was found that external factors, touch force and temperature, can have a large impact on the resulting waveform, so the effects of those factors need to be considered in order for the information to become more reliable.

Computational Modelling of Glucose Uptake by SGLT1 and Apical GLUT2 in the Enterocyte

It has been suggested that glucose absorption in the small intestine depends on both constitutively expressed SGLT1 and translocated GLUT2 in the brush border membrane, especially in the presence of high levels of luminal glucose. Here, we present a computational model of non-isotonic glucose uptake by small intestinal epithelial cells. The model incorporates apical uptake via SGLT1 and GLUT2, basolateral efflux into the blood via GLUT2, and cellular volume changes in response to non-isotonic conditions. The dependence of glucose absorption on luminal glucose, blood flow rate, and inlet blood glucose concentration is studied. Uptake via apical GLUT2 is found to be sensitive to all these factors. Under a range of conditions, the maximum apical GLUT2 flux is about half of the SGLT1 flux and is achieved at high luminal glucose (&gt; 50 mM), high blood flow rates, and low inlet blood concentrations. In contrast, SGLT1 flux is less sensitive to these factors. When luminal glucose concentration is less than 10 mM, apical GLUT2 serves as an efflux pathway for glucose to move from the blood to the lumen. The model results indicate that translocation of GLUT2 from the basolateral to the apical membrane increases glucose uptake into the cell; however, the reduction of efflux capacity results in a decrease in net absorption. Recruitment of GLUT2 from a cytosolic pool elicits a 10–20% increase in absorption for luminal glucose levels in the a 20–100 mM range. Increased SGLT1 activity also leads to a roughly 20% increase in absorption. A concomitant increase in blood supply results in a larger increase in absorption. Increases in apical glucose transporter activity help to minimise cell volume changes by reducing the osmotic gradient between the cell and the lumen.