Engagement of the inhibitory receptor CD158a interrupts TCR signaling,preventing dynamic membrane reorganization in CTL/tumor cell interaction

Renal cell carcinoma (RCC) infiltrating lymphocytes (TILs) express killer cell immunoglobulinlike receptors (KIRs) that inhibit the antitumor CD8(+) T-cell lysis. In the present study, to better examine the functional consequences of KIR engagement on cytotoxic T lymphocyte (CTL)/tumor interaction, we have investigated the influence of KIR CD158a on early steps of T-cell activation. We show that coengagement of T-cell receptor (TCR) and CD158a by tumor cells inhibited tyrosine phosphorylation of early signaling proteins ZAP-70 and LAT, lipid raft coalescence, and TCR/CD3 accumulation at the CTL/tumor cell interface. In addition, the guanine exchange factor Vav was not phosphorylated, and no actin cytoskeleton rearrangement was observed. Our data indicate a role of KIR CD158a in the dynamic events induced by TCR triggering, preventing CTL membrane reorganization, and subsequent completion of CTL activation program. Accordingly, the expression of CD158 by TILs may favor tumor cell escape to the immune response.     

Doppler reference values of the fetal vertebral and middle cerebral arteries,at 19–41 weeks gestation

Objectives: Blood flow to the fetal brain is supplied by two vascular systems: the vertebral artery (VA) and the internal carotid artery with its anatomical continuation, the middle cerebral artery (ICA/MCA). In this work, our aim was to establish consistent reference values for the comparative study of both arterial systems.

Methods: The study group consisted of 2323 Doppler examinations of the VA, MCA and UA performed on 2323 single pregnancies between 19 and 41 weeks. These values were afterwards used to calculate the pulsatility index (PI), peak systolic velocity (PSV) and cerebro-placental ratio (CPR) percentiles.

Results: The VA and MCA PI reached maximum values at the end of the second trimester and decreased afterwards due to an increase in the diastolic flow. Conversely, the VA and MCA PSV increased progressively until the end of pregnancy. Regarding the VA and MCA CPR values, they were higher in the middle of the third trimester and decreased afterwards.

Conclusions: In both arterial systems, Doppler reference values have been calculated for the PI, PSV and CPR, being available for future comparative studies.     

Capacitive performance of vertically aligned reduced titania nanotubes coated with Mn2O3 by reverse pulse electrodeposition

In this study, a composite material, manganese oxide/reduced titania nanotubes (Mn₂O₃/R-TNTs), was synthesized through incorporation of Mn₂O₃ onto R-TNTs via the reverse pulse electrodeposition technique. The influence of pulse reverse duty cycles on the morphological, structural and electrochemical performance of the surface was studied by varying the applied duty cycle from 10% to 90% for 5 min total on-time at an alternate potential of −0.90 V (E_on) and 0.00 V (E_off). FESEM analysis revealed the uniform deposition of Mn₂O₃ on the circumference of the nanotubes. The amount of Mn₂O₃ loaded onto the R-TNTs increased as a higher duty cycle was applied. Cyclic voltammetry and galvanostatic charge–discharge tests were employed to elucidate the electrochemical properties of all the synthesized samples in 1 M KCl. The specific capacitance per unit area was greatly enhanced upon the incorporation of Mn₂O₃ onto R-TNTs, but showed a decrease as a high duty cycle was applied. This proved that low amounts of Mn₂O₃ loading enhanced the facilitation of the active ions for charge storage purposes. The optimized sample, Mn₂O₃/R-TNTs synthesized at 10% duty cycle, exhibited high specific capacitance of 18.32 mF cm⁻² at a current density of 0.1 mA cm⁻² obtained from constant current charge–discharge measurements. This revealed that the specific capacitance possessed by Mn₂O₃/R-TNTs synthesized at 10% duty cycle was 6 times higher than bare R-TNTs.

Mn₂O₃ was coated onto reduced titania nanotubes by reverse pulse electrodeposition, showing smooth and homogenous deposits without covering the opening of the nanotubes.     

Ethyl glucuronide and ethyl sulfate: a review of their roles in forensic toxicology analysis of alcohol postmortem

Forensic Toxicology - This review presents the current methods used for determining ethyl glucuronide (EtG) and ethyl sulfate (EtS) concentrations in postmortem specimens, including sample...     

Effects of the selective oestrogen receptor modulator-raloxifene-on calcium and PTH secretory dynamics in women with osteoporosis

OBJECTIVES: A possible mechanism for the maintenance of bone mass by oestrogens and the selective oestrogen receptor modulator (SERM)-raloxifene-is an interaction with calciotropic hormones. We studied the effects of raloxifene on calcium-PTH homeostasis. PATIENTS AND MEASUREMENTS: Calcium and EDTA infusions were performed in 32 post-menopausal women with osteoporosis (BMD T score < - 2.5). This cross-sectional study was performed in the third year of the MORE (Multiple Outcomes of Raloxifene Evaluation) trial, a double-blind, placebo-controlled study. After an overnight fast, calcium glubionate (5 mg/kg BW*h), and after 2.5 h of test-free interval, Na3EDTA (40 mg/kg BW*h) were given intravenously. The duration of infusions was based on individual plasma total calcium before the calcium infusion (t = 0), the target calcium (2.60 and 1.95 mmol/l, respectively), and desired mean calcium change (0.010 mmol/L*min). Blood samples were taken at 0 and every 5 minutes of both infusions. Plasma PTH levels were fitted into an inversed sigmoidal relation with plasma calcium. The effect of raloxifene on calcium-PTH homeostasis was tested in linear regression models adjusted for age and BMI. Nine patients used placebo, 13 raloxifene 60 mg/day and 10 raloxifene 120 mg/day. RESULTS: Raloxifene use was associated with lower plasma albumin (40.7 +/- 1.8 vs. 38.0 +/- 2.0 and 38.5 +/- 2.3 g/l, for placebo, raloxifene 60 mg/day and raloxifene 120 mg/day, respectively, P = 0.01), lower plasma total calcium at t = 0 (2.28 vs. 2.24 and 2.21; +/- 0.07 mmol/L; P = 0.03), lower plasma total calcium at 50% of maximal PTH secretion (PTH set-point: 2.23 +/- 0.06 vs. 2.18 +/- 0.07 and 2.16 +/- 0.08 mmol/l, P = 0.06), and lower plasma non-suppressible PTH (0.84 +/- 0.19 vs. 0.75 +/- 0.10 and 0.73 +/- 0.05 pmol/l, P = 0.02). After correction for plasma albumin, the differences for plasma calcium at t = 0 and at PTH set-point were no longer significant. In contrast, the difference in PTH suppression during calcium load was not explained either by differences in plasma albumin or calcium. CONCLUSION: Raloxifene did not have any detectable effect on the PTH set-point. An effect on non-suppressible PTH secretion cannot be excluded.     

Use of Intravenous Thrombolysis in Acute Ischemic Stroke Management in Patients with Active Malignancies: A Topical Review

ObjectivesOur review aims to present existing data on the safety of Intravenous thrombolysis (IVT) use in acute ischemic stroke (AIS) patients with concomitant central nervous system or systemic malignancies, with attention to special circumstances pertaining to specific cancer subtypes to help in acute decision making, especially for neurologists and emergency medicine physicians.MethodsA literature search was conducted on electronic databases inclusive of Medline, EMBASE and CINAHL for articles published or available in English between January 1, 2000 to June 1, 2020 using the following search terms: “acute ischemic stroke,” “cerebrovascular disease,” “Intravenous thrombolysis,” “tissue plasminogen activator,” “cancer patients,” and “neoplasm”.ConclusionRecognition of stroke symptoms in patients with active cancer, in particularly those involving the brain, requires astute clinical judgement. Decision-making can be improved by understanding baseline functional status, cancer prognosis and expected disability from stroke, as well as utilizing diagnostic modalities such acute MRI where needed. While this article does not encourage use of IVT in patients with all malignancies, it lays the groundwork for decision making should thrombolysis be a consideration in a patient with AIS in a cancer patient.     

Annexin A1–containing extracellular vesicles and polymeric nanoparticles promote epithelial wound repair

Epithelial restitution is an essential process that is required to repair barrier function at mucosal surfaces following injury. Prolonged breaches in epithelial barrier function result in inflammation and further damage; therefore, a better understanding of the epithelial restitution process has potential for improving the development of therapeutics. In this work, we demonstrate that endogenous annexin A1 (ANXA1) is released as a component of extracellular vesicles (EVs) derived from intestinal epithelial cells, and these ANXA1-containing EVs activate wound repair circuits. Compared with healthy controls, patients with active inflammatory bowel disease had elevated levels of secreted ANXA1-containing EVs in sera, indicating that ANXA1-containing EVs are systemically distributed in response to the inflammatory process and could potentially serve as a biomarker of intestinal mucosal inflammation. Local intestinal delivery of an exogenous ANXA1 mimetic peptide (Ac2-26) encapsulated within targeted polymeric nanoparticles (Ac2-26 Col IV NPs) accelerated healing of murine colonic wounds after biopsy-induced injury. Moreover, one-time systemic administration of Ac2-26 Col IV NPs accelerated recovery following experimentally induced colitis. Together, our results suggest that local delivery of proresolving peptides encapsulated within nanoparticles may represent a potential therapeutic strategy for clinical situations characterized by chronic mucosal injury, such as is seen in patients with IBD.     

Gut Commensal Bacteria and Regional Wnt Gene Expression in the Proximal Versus Distal Colon

Regional expression of Wingless/Int (Wnt) genes plays a central role in regulating intestinal development and homeostasis. However, our knowledge of such regional Wnt proteins in the colon remains limited. To understand further the effect of Wnt signaling components in controlling intestinal epithelial homeostasis, we investigated whether the physiological heterogeneity of the proximal and distal colon can be explained by differential Wnt signaling. With the use of a Wnt signaling-specific PCR array, expression of 84 Wnt-mediated signal transduction genes was analyzed, and a differential signature of Wnt-related genes in the proximal versus distal murine colon was identified. Several Wnt agonists (Wnt5a, Wnt8b, and Wnt11), the Wnt receptor frizzled family receptor 3, and the Wnt inhibitory factor 1 were differentially expressed along the colon length. These Wnt signatures were associated with differential epithelial cell proliferation and migration in the proximal versus distal colon. Furthermore, reduced Wnt/β-catenin activity and decreased Wnt5a and Wnt11 expression were observed in mice lacking commensal bacteria, an effect that was reversed by conventionalization of germ-free mice. Interestingly, myeloid differentiation primary response gene 88 knockout mice showed decreased Wnt5a levels, indicating a role for Toll-like receptor signaling in regulating Wnt5a expression. Our results suggest that the morphological and physiological heterogeneity within the colon is in part facilitated by the differential expression of Wnt signaling components and influenced by colonization with bacteria.One of the fundamental aspects in the development of the gastrointestinal tract is the spatiotemporal expression of signaling molecules that regulate cell fate and differentiation. Previous studies have highlighted a central role of the evolutionarily conserved Wingless/Int (Wnt) signaling pathways as key regulators of embryonic development and epithelial homeostasis in the gut.^1–3 In development, local expression patterns of Wnt signaling components play an important role in organogenesis.^4,5 Wnt signals control important biological processes required for cell proliferation, differentiation, polarity, and movement, depending on the target cell and the cellular environment.Recent reports have highlighted the importance of understanding the role of Wnt signaling in the intestinal tract. The intestinal epithelium is highly dynamic and, depending on the species and location, is actively turned over in <1 week.⁶ Wnt/β-catenin signaling regulates intestinal epithelial cell (IEC) homeostasis and proliferation by increasing β-catenin stability in crypt epithelial cells, whereas IEC migration and differentiation are believed to be in part facilitated through noncanonical (Wnt) signaling pathways independent of β-catenin.^6,7 The renewal of intestinal epithelia requires a delicate balance of signaling proteins to control epithelial cell proliferation and migration that in turn is vital for maintaining mucosal homeostasis. Interestingly, regional differences in Wnt gene expression in small versus large intestine are observed in adult mice, suggesting the importance of differential local Wnt expression in regulation of intestinal mucosal homeostasis.⁷Although the entire colon exhibits considerable morphological and physiological heterogeneity along its length,^8–11 the expression pattern of Wnt signaling components in the different regions of the adult colon remains poorly understood. Embryologically, the cecum, ascending colon, and the proximal two-thirds of the transverse colon are derived from the midgut, whereas the distal colon originates from the hindgut. Such distinct origins of the colonic segment support specific biological characteristics and suggest that distinct regulatory factors are likely to control epithelial homeostasis in the proximal versus distal colon. In addition, important contributing factors that influence Wnt/β-catenin signaling and intestinal epithelial proliferation might be microbial communities that localize in the intestine in distinct regions.^6,12 Such a delicate physiological balance of Wnt signaling and intestinal epithelial homeostasis is further perturbed in mucosal inflammatory and neoplastic diseases,^3,13 which also indicate regional differences in the proximal versus distal colonic segments.^14–17In the present study, we investigate the regional heterogeneity of Wnt genes in the proximal versus distal colon. Given the importance of luminal microbiota in influencing intestinal epithelial homeostasis¹⁸ and to determine whether the Wnt signatures are influenced by microflora colonization, we examined expression of Wnt proteins in the colonic segments of mice raised under germ-free (GF) conditions.