Local hyperthermia therapy induces browning of white fat and treats obesity.

Beige fat plays key roles in the regulation of systemic energy homeostasis; however, detailed mechanisms and safe strategy for its activation remain elusive. In this study, we discovered that local hyperthermia therapy (LHT) targeting beige fat promoted its activation in humans and mice. LHT achieved using a hydrogel-based photothermal therapy activated beige fat, preventing and treating obesity in mice without adverse effects. HSF1 is required for the effects since HSF1 deficiency blunted the metabolic benefits of LHT. HSF1 regulates Hnrnpa2b1 (A2b1) transcription, leading to increased mRNA stability of key metabolic genes. Importantly, analysis of human association studies followed by functional analysis revealed that the HSF1 gain-of-function variant p.P365T is associated with improved metabolic performance in humans and increased A2b1 transcription in mice and cells. Overall, we demonstrate that LHT offers a promising strategy against obesity by inducing beige fat activation via HSF1-A2B1 transcriptional axis.

Gold nanorod-assisted theranostic solution for nonvisible residual disease in bladder cancer.

Residual nonvisible bladder cancer after proper treatment caused by technological and therapeutic limitations is responsible for tumor relapse and progression. This study aimed to demonstrate the feasibility of a solution for simultaneous detection and treatment of bladder cancer lesions smaller than one millimeter. The α5ß1 integrin was identified as a specific marker in 81% of human high-grade nonmuscle invasive bladder cancers and used as a target for the delivery of targeted gold nanorods (GNRs). In a preclinical model of orthotopic bladder cancer expressing the α5ß1 integrin, the photoacoustic imaging of targeted GNRs visualized lesions smaller than one millimeter, and their irradiation with continuous laser was used to induce GNR-assisted hyperthermia. Necrosis of the tumor mass, improved survival, and computational modeling were applied to demonstrate the efficacy and safety of this solution. Our study highlights the potential of the GNR-assisted theranostic strategy as a complementary solution in clinical practice to reduce the risk of nonvisible residual bladder cancer after current treatment. Further validation through clinical studies will support the findings of the present study.

Calcium Channelopathies: Structural Insights into Disorders of the Muscle Excitation-Contraction Complex.

Ion channels are membrane proteins responsible for the passage of ions down their electrochemical gradients and across biological membranes. In this, they generate and shape action potentials and provide secondary messengers for various signaling pathways. They are often part of larger complexes containing auxiliary subunits and regulatory proteins. Channelopathies arise from mutations in the genes encoding ion channels or their associated proteins. Recent advances in cryo-electron microscopy have resulted in an explosion of ion channel structures in multiple states, generating a wealth of new information on channelopathies. Disease-associated mutations fall into different categories, interfering with ion permeation, protein folding, voltage sensing, ligand and protein binding, and allosteric modulation of channel gating. Prime examples of these are Ca2+-selective channels expressed in myocytes, for which multiple structures in distinct conformational states have recently been uncovered. We discuss the latest insights into these calcium channelopathies from a structural viewpoint.

Heat-hypersensitive mutants of ryanodine receptor type 1 revealed by microscopic heating.

Thermoregulation is an important aspect of human homeostasis, and high temperatures pose serious stresses for the body. Malignant hyperthermia (MH) is a life-threatening disorder in which body temperature can rise to a lethal level. Here we employ an optically controlled local heat-pulse method to manipulate the temperature in cells with a precision of less than 1 °C and find that the mutants of ryanodine receptor type 1 (RyR1), a key Ca2+ release channel underlying MH, are heat hypersensitive compared with the wild type (WT). We show that the local heat pulses induce an intracellular Ca2+ burst in human embryonic kidney 293 cells overexpressing WT RyR1 and some RyR1 mutants related to MH. Fluorescence Ca2+ imaging using the endoplasmic reticulum-targeted fluorescent probes demonstrates that the Ca2+ burst originates from heat-induced Ca2+ release (HICR) through RyR1-mutant channels because of the channels' heat hypersensitivity. Furthermore, the variation in the heat hypersensitivity of four RyR1 mutants highlights the complexity of MH. HICR likewise occurs in skeletal muscles of MH model mice. We propose that HICR contributes an additional positive feedback to accelerate thermogenesis in patients with MH.

Molecular mechanism of the severe MH/CCD mutation Y522S in skeletal ryanodine receptor (RyR1) by cryo-EM.

Ryanodine receptors (RyRs) are main regulators of intracellular Ca2+ release and muscle contraction. The Y522S mutation of RyR1 causes central core disease, a weakening myopathy, and malignant hyperthermia, a sudden and potentially fatal response to anesthetics or heat. Y522 is in the core of the N-terminal subdomain C of RyR1 and the mechanism of how this mutation orchestrates malfunction is unpredictable for this 2-MDa ion channel, which has four identical subunits composed of 15 distinct cytoplasmic domains each. We expressed and purified the RyR1 rabbit homolog, Y523S, from HEK293 cells and reconstituted it in nanodiscs under closed and open states. The high-resolution cryogenic electron microscopic (cryo-EM) three-dimensional (3D) structures show that the phenyl ring of Tyr functions in a manner analogous to a "spacer" within an α-helical bundle. Mutation to the much smaller Ser alters the hydrophobic network within the bundle, triggering rearrangement of its α-helices with repercussions in the orientation of most cytoplasmic domains. Examining the mutation-induced readjustments exposed a series of connected α-helices acting as an ∼100 Å-long lever: One end protrudes toward the dihydropyridine receptor, its molecular activator (akin to an antenna), while the other end reaches the Ca2+ activation site. The Y523S mutation elicits channel preactivation in the absence of any activator and full opening at 1.5 µM free Ca2+, increasing by ∼20-fold the potency of Ca2+ to activate the channel compared with RyR1 wild type (WT). This study identified a preactivated pathological state of RyR1 and a long-range lever that may work as a molecular switch to open the channel.

Wireless Photoactivated Targeted Nanosystem for Oncotherapy Via Synergistic Effects of Hyperthermia/Redox Stress Amplification/GSK-3ß Activity Inhibition.

Highly soluble salts and gas mediated therapies are emerging antitumor strategies. However, the therapeutic efficacy remains restricted by difficulty in delivering them to the tumor site and poorly controlled release in deep tissues. Here, an intelligent wireless photoactivated targeted nanosystem is designed for delivering LiCl and H2 to tumors for therapy. LiCl causes cell death by inhibiting the activity of GSK-3ß. H2 selectively interacts with reactive oxygen species in the tumor, leading to redox stress, which induces apoptosis. The significant heat generated by the nanosystem not only kills tumor cells but also accelerates the dissolution of LiCl and the release of H2. The rapid dissolution of LiCl leads to a surge in intracellular osmotic pressure, which further intensifies the redox stress response and enhances the efficiency of therapy. The nanosystem shows efficient tumor therapeutic capability via synergistic effects of hyperthermia/redox stress amplification/GSK-3ß activity inhibition.

Intracellular Magnetic Hyperthermia Enables Concurrent Down-Regulation of CD47 and SIRPα To Potentiate Antitumor Immunity.

Harnessing the potential of tumor-associated macrophages (TAMs) to engulf tumor cells offers promising avenues for cancer therapy. Targeting phagocytosis checkpoints, particularly the CD47-signal regulatory protein α (SIRPα) axis, is crucial for modulating TAM activity. However, single checkpoint inhibition has shown a limited efficacy. In this study, we demonstrate that ferrimagnetic vortex-domain iron oxide (FVIO) nanoring-mediated magnetic hyperthermia effectively suppresses the expression of CD47 protein on Hepa1-6 tumor cells and SIRPα receptor on macrophages, which disrupts CD47-SIRPα interaction. FVIO-mediated magnetic hyperthermia also induces immunogenic cell death and polarizes TAMs toward M1 phenotype. These changes collectively bolster the phagocytic ability of macrophages to eliminate tumor cells. Furthermore, FVIO-mediated magnetic hyperthermia concurrently escalates cytotoxic T lymphocyte levels and diminishes regulatory T cell levels. Our findings reveal that magnetic hyperthermia offers a novel approach for dual down-regulation of CD47 and SIRPα, reshaping the tumor microenvironment to stimulate immune responses, culminating in significant antitumor activity.

Heat-related changes in the velocity and kinetic energy of flowing blood influence the human heart's output during hyperthermia.

Passive whole-body hyperthermia increases limb blood flow and cardiac output ( Q ̇ $\dot Q$ ), but the interplay between peripheral and central thermo-haemodynamic mechanisms remains unclear. Here we tested the hypothesis that local hyperthermia-induced alterations in peripheral blood flow and blood kinetic energy modulate flow to the heart and Q ̇ $\dot Q$ . Body temperatures, regional (leg, arm, head) and systemic haemodynamics, and left ventricular (LV) volumes and functions were assessed in eight healthy males during: (1) 3 h control (normothermic condition); (2) 3 h of single-leg heating; (3) 3 h of two-leg heating; and (4) 2.5 h of whole-body heating. Leg, forearm, and extracranial blood flow increased in close association with local rises in temperature while brain perfusion remained unchanged. Increases in blood velocity with small to no changes in the conduit artery diameter underpinned the augmented limb and extracranial perfusion. In all heating conditions, Q ̇ $\dot Q$ increased in association with proportional elevations in systemic vascular conductance, related to enhanced blood flow, blood velocity, vascular conductance and kinetic energy in the limbs and head (all R2 ≥ 0.803; P < 0.001), but not in the brain. LV systolic (end-systolic elastance and twist) and diastolic functional profiles (untwisting rate), pulmonary ventilation and systemic aerobic metabolism were only altered in whole-body heating. These findings substantiate the idea that local hyperthermia-induced selective alterations in peripheral blood flow modulate the magnitude of flow to the heart and Q ̇ $\dot Q$ through changes in blood velocity and kinetic energy. Localised heat-activated events in the peripheral circulation therefore affect the human heart's output. KEY POINTS: Local and whole-body hyperthermia increases limb and systemic perfusion, but the underlying peripheral and central heat-sensitive mechanisms are not fully established. Here we investigated the regional (leg, arm and head) and systemic haemodynamics (cardiac output: Q ̇ $\dot Q$ ) during passive single-leg, two-leg and whole-body hyperthermia to determine the contribution of peripheral and central thermosensitive factors in the control of human circulation. Single-leg, two-leg, and whole-body hyperthermia induced graded increases in leg blood flow and Q ̇ $\dot Q$ . Brain blood flow, however, remained unchanged in all conditions. Ventilation, extracranial blood flow and cardiac systolic and diastolic functions only increased during whole-body hyperthermia. The augmented Q ̇ $\dot Q$ with hyperthermia was tightly related to increased limb and head blood velocity, flow and kinetic energy. The findings indicate that local thermosensitive mechanisms modulate regional blood velocity, flow and kinetic energy, thereby controlling the magnitude of flow to the heart and thus the coupling of peripheral and central circulation during hyperthermia.

Putative malignant hyperthermia mutation CaV1.1-R174W is insufficient to trigger a fulminant response to halothane or confer heat stress intolerance.

Malignant hyperthermia susceptibility (MHS) is an autosomal dominant pharmacogenetic disorder that manifests as a hypermetabolic state when carriers are exposed to halogenated volatile anesthetics or depolarizing muscle relaxants. In animals, heat stress intolerance is also observed. MHS is linked to over 40 variants in RYR1 that are classified as pathogenic for diagnostic purposes. More recently, a few rare variants linked to the MHS phenotype have been reported in CACNA1S, which encodes the voltage-activated Ca2+ channel CaV1.1 that conformationally couples to RyR1 in skeletal muscle. Here, we describe a knock-in mouse line that expresses one of these putative variants, CaV1.1-R174W. Heterozygous (HET) and homozygous (HOM) CaV1.1-R174W mice survive to adulthood without overt phenotype but fail to trigger with fulminant malignant hyperthermia when exposed to halothane or moderate heat stress. All three genotypes (WT, HET, and HOM) express similar levels of CaV1.1 by quantitative PCR, Western blot, [3H]PN200-110 receptor binding and immobilization-resistant charge movement densities in flexor digitorum brevis fibers. Although HOM fibers have negligible CaV1.1 current amplitudes, HET fibers have similar amplitudes to WT, suggesting a preferential accumulation of the CaV1.1-WT protein at triad junctions in HET animals. Never-the-less both HET and HOM have slightly elevated resting free Ca2+ and Na+ measured with double barreled microelectrode in vastus lateralis that is disproportional to upregulation of transient receptor potential canonical (TRPC) 3 and TRPC6 in skeletal muscle. CaV1.1-R174W and upregulation of TRPC3/6 alone are insufficient to trigger fulminant malignant hyperthermia response to halothane and/or heat stress in HET and HOM mice.

A bout of aerobic exercise in the heat increases carbohydrate use but does not enhance the disposal of an oral glucose load, in healthy active individuals.

We investigated if a bout of exercise in a hot environment (HEAT) would reduce the postprandial hyperglycemia induced by glucose ingestion. The hypothesis was that HEAT stimulating carbohydrate oxidation and glycogen use would increase the disposal of an ingested glucose load [i.e., oral glucose tolerance test (OGTT); 75 g of glucose]. Separated by at least 1 wk, nine young healthy individuals underwent three trials after an overnight fast in a randomized order. Two trials included 50 min of pedaling at 58 ± 5% V̇o2max either in a thermoneutral (21 ± 1°C; NEUTRAL) or in a hot environment (33 ± 1°C; HEAT) eliciting similar energy expenditure (503 ± 101 kcal). These two trials were compared with a no-exercise trial (NO EXER). Twenty minutes after exercise (or rest), subjects underwent an OGTT, while carbohydrate oxidation (CHOxid, using indirect calorimetry) plasma blood glucose, insulin concentrations (i.e., [glucose], [insulin]), and double tracer glucose kinetics ([U-13C] glucose ingestion and [6,6-2H2] glucose infusion) were monitored for 120 min. At rest, [glucose], [insulin], and rates of appearance/disappearance of glucose in plasma (glucose Ra/Rd) were similar among trials. During exercise, heart rate, tympanic temperature, [glucose], glycogen oxidation, and total CHOxid were higher during HEAT than NEUTRAL (i.e., 149 ± 35 vs. 124 ± 31 µmol·kg-1·min-1, P = 0.010). However, during the following OGTT, glucose Rd was similar in HEAT and NEUTRAL trials (i.e., 25.1 ± 3.6 vs. 25.2 ± 5.3 µmol·kg-1·min-1, P = 0.981). Insulin sensitivity (i.e., ISIndexMATSUDA) only improved in NEUTRAL compared with NO EXER (10.1 ± 4.6 vs. 8.8 ± 3.7 au; P = 0.044). In summary, stimulating carbohydrate use with exercise in a hot environment does not improve postprandial plasma glucose disposal or insulin sensitivity in a subsequent OGTT.NEW & NOTEWORTHY Exercise in the heat increases estimated muscle glycogen use. Reduced muscle glycogen after exercise in the heat could increase insulin-mediated glucose uptake during a subsequent oral glucose tolerance test (OGTT). However, plasma glucose kinetics are not improved during the OGTT in response to a bout of exercise in the heat, and insulin sensitivity worsens. Heat stress activates glucose counterregulatory hormones whose actions may linger during the OGTT, preventing increased glucose uptake.

Oxygen fluctuations in the brain and periphery induced by intravenous fentanyl: effects of dose and drug experience.

Fentanyl is the leading contributor to drug overdose deaths in the United States. Its potency, rapid onset of action, and lack of effective reversal treatment make the drug much more lethal than other opioids. Although it is understood that fentanyl is dangerous at higher doses, the literature surrounding fentanyl's physiological effects remains contradictory at lower doses. To explore this discrepancy, we designed a study incorporating electrochemical assessment of oxygen in the brain (nucleus accumbens) and subcutaneous space, multisite thermorecording (brain, skin, muscle), and locomotor activity at varying doses of fentanyl (1.0, 3.0, 10, 30, and 90 µg/kg) in rats. In the nucleus accumbens, lower doses of fentanyl (3.0 and 10 µg/kg) led to an increase in oxygen levels while higher doses (30 and 90 µg/kg) led to a biphasic pattern, with an initial dose-dependent decrease followed by an increase. In the subcutaneous space, oxygen decreases started to appear at relatively lower doses (>3 µg/kg), had shorter onset latencies, and were stronger and prolonged. In the temperature experiment, lower doses of fentanyl (1.0, 3.0, and 10 µg/kg) led to an increase in brain, skin, and muscle temperatures, while higher doses (30 and 90 µg/kg) resulted in a dose-dependent biphasic temperature change, with an increase followed by a prolonged decrease. We also compared oxygen and temperature responses induced by fentanyl over six consecutive days and found no evidence of tolerance in both parameters. In conclusion, we report that fentanyl's effects are highly dose-dependent, drawing attention to the importance of better characterization to adequately respond in emergent cases of illicit fentanyl misuse.NEW & NOTEWORTHY By using electrochemical oxygen sensors in freely moving rats, we show that intravenous fentanyl induces opposite changes in brain oxygen at varying doses, increasing at lower doses (<10 µg/kg) and inducing a biphasic response, decrease followed by increase, at higher doses (>10-90 µg/kg). In contrast, fentanyl-induced dose-dependent oxygen decreases in the subcutaneous space. We consider the mechanisms underlying distinct oxygen responses in the brain and periphery and discuss naloxone's role in alleviating fentanyl-induced brain hypoxia.

Electrical Stimulation Promotes Endocytosis of Magnetic Nanoparticles by Cancer Cells.

Nanomaterials are increasingly used in biomedical imaging and cancer therapy, and how to improve the endocytosis of nanomaterials by cells is a key issue. The application of alternating current (AC) electrical stimulation to osteosarcoma cells (MG-63) here can increase the cellular endocytosis of Fe3O4 nanoparticles (diameter: 50 nm) by 52.46% via macropinocytosis. This can be ascribed to the decrease in F-actin content and the increase in intracellular Ca2+ concentration. Transmission electron microscope, immunofluorescence staining, western blot, flow cytometry, and inductively coupled plasma emission spectrometer analyses support this interpretation. The application of electrical stimulation decreases the cell viability in magnetic hyperthermia by 47.6% and increases the signal intensity of magnetic resonance imaging by 29%. Similar enhanced endocytosis is observed for breast cancer cells (MCF-7), glioblastoma cells (U-87 MG), melanoma cells (A-375), and bladder cancer cells (TCCSUP), and also for Fe3O4 nanoparticles with the diameters of 20 and 100 nm, and Zn0.54Co0.46Cr0.65Fe1.35O4 nanoparticles with the diameter of 70 nm. It seems the electrical stimulation has the potential to improve the diagnostic and therapeutic effects of magnetic nanoparticles by promoting endocytosis.

Nanomaterial-Enabled Photothermal Heating and Its Use for Cancer Therapy via Localized Hyperthermia.

Photothermal therapy (PTT), which employs nanoscale transducers delivered into a tumor to locally generate heat upon irradiation with near-infrared light, shows great potential in killing cancer cells through hyperthermia. The efficacy of such a treatment is determined by a number of factors, including the amount, distribution, and dissipation of the generated heat, as well as the type of cancer cell involved. The amount of heat generated is largely controlled by the number of transducers accumulated inside the tumor, the absorption coefficient and photothermal conversion efficiency of the transducer, and the irradiance of the light. The efficacy of treatment depends on the distribution of the transducers in the tumor and the penetration depth of the light. The vascularity and tissue thermal conduction both affect the dissipation of heat and thereby the distribution of temperature. The successful implementation of PTT in the clinic setting critically depends on techniques for real-time monitoring and management of temperature.

Injectable Hydrogels Including Magnetic Nanosheets for Multidisciplinary Treatment of Hepatocellular Carcinoma via Magnetic Hyperthermia.

Relapse and unresectability have become the main obstacle for further improving hepatocellular carcinoma (HCC) treatment effect. Currently, single therapy for HCC in clinical practice is limited by postoperative recurrence, intraoperative blood loss and poor patient outcomes. Multidisciplinary therapy has been recognized as the key to improving the long-term survival rate for HCC. However, the clinical application of HCC synthetic therapy is restricted by single functional biomaterials. In this study, a magnetic nanocomposite hydrogel (CG-IM) with iron oxide nanoparticle-loaded mica nanosheets (Iron oxide nanoparticles@Mica, IM) is reported. This biocompatible magnetic hydrogel integrated high injectability, magnetocaloric property, mechanical robustness, wet adhesion, and hemostasis, leading to efficient HCC multidisciplinary therapies including postoperative tumor margin treatment and percutaneous locoregional ablation. After minimally invasive hepatectomy of HCC, the CG-IM hydrogel can facilely seal the bleeding hepatic margin, followed by magnetic hyperthermia ablation to effectively prevent recurrence. In addition, CG-IM hydrogel can inhibit unresectable HCC by magnetic hyperthermia through the percutaneous intervention under ultrasound guidance.

Magnetic Nanoparticles: A Review on Synthesis, Characterization, Functionalization, and Biomedical Applications.

Nowadays, magnetic nanoparticles (MNPs) are applied in numerous fields, especially in biomedical applications. Since biofluidic samples and biological tissues are nonmagnetic, negligible background signals can interfere with the magnetic signals from MNPs in magnetic biosensing and imaging applications. In addition, the MNPs can be remotely controlled by magnetic fields, which make it possible for magnetic separation and targeted drug delivery. Furthermore, due to the unique dynamic magnetizations of MNPs when subjected to alternating magnetic fields, MNPs are also proposed as a key tool in cancer treatment, an example is magnetic hyperthermia therapy. Due to their distinct surface chemistry, good biocompatibility, and inducible magnetic moments, the material and morphological structure design of MNPs has attracted enormous interest from a variety of scientific domains. Herein, a thorough review of the chemical synthesis strategies of MNPs, the methodologies to modify the MNPs surface for better biocompatibility, the physicochemical characterization techniques for MNPs, as well as some representative applications of MNPs in disease diagnosis and treatment are provided. Further portions of the review go into the diagnostic and therapeutic uses of composite MNPs with core/shell structures as well as a deeper analysis of MNP properties to learn about potential biomedical applications.

Photoactivated Hydrogel Therapeutic System with MXene-Based Nanoarchitectonics Potentiates Endogenous Bone Repair Through Reshaping the Osteo-Vascularization Network.

The repair and reconstruction of large-scale bone defects face enormous challenges because of the failure to reconstruct the osteo-vascularization network. Herein, a near-infrared (NIR) light-responsive hydrogel system is reported to achieve programmed tissue repair and regeneration through the synergetic effects of on-demand drug delivery and mild heat stimulation. The spatiotemporal hydrogel system (HG/MPa) composed of polydopamine-coated Ti3C2Tx MXene (MP) nanosheets decorated with acidic fibroblast growth factor (aFGF, a potent angiogenic drug) and hydroxypropyl chitosan/gelatin (HG) hydrogel is developed to orchestrate the reconstruction of the osteo-vascularization network and boost bone regeneration. Upon exposure to NIR light irradiation, the engineered HG/MPa hydrogel can achieve the initial complete release of aFGF to induce rapid angiogenesis and provide sufficient blood supply, maximizing its biofunction in the defect area. This integrated hydrogel system demonstrated good therapeutic efficacy in promoting cell adhesion, proliferation, migration, angiogenesis, and osteogenic differentiation through periodic NIR irradiation. In vivo, animal experiments further revealed that the spatiotemporalized hydrogel platform synergized with mild photothermal treatment significantly accelerated critical-sized bone defect healing by increasing the osteo-vascularization network density, recruiting endogenous stem cells, and facilitating the production of osteogenesis/angiogenesis-related factors. Overall, smart-responsive hydrogel could enhance the reconstruction of the osteo-vascularization network in bone regeneration.

Metal-Organic Framework as a New Type of Magnetothermally-Triggered On-Demand Release Carrier.

The development of external stimuli-controlled payload systems has been sought after with increasing interest toward magnetothermally-triggered drug release (MTDR) carriers due to their non-invasive features. However, current MTDR carriers present several limitations, such as poor heating efficiency caused by the aggregation of iron oxide nanoparticles (IONPs) or the presence of antiferromagnetic phases which affect their efficiency. Herein, a novel MTDR carrier is developed using a controlled encapsulation method that fully fixes and confines IONPs of various sizes within the metal-organic frameworks (MOFs). This novel carrier preserves the MOF's morphology, porosity, and IONP segregation, while enhances heating efficiency through the oxidation of antiferromagnetic phases in IONPs during encapsulation. It also features a magnetothermally-responsive nanobrush that is stimulated by an alternating magnetic field to enable on-demand drug release. The novel carrier shows improved heating, which has potential applications as contrast agents and for combined chemo and magnetic hyperthermia therapy. It holds a great promise for magneto-thermally modulated drug dosing at tumor sites, making it an exciting avenue for cancer treatment.

Effect of elevated temperature and hydrocortisone addition on the proliferation of fibroblasts.

Hyperthermia along with hydrocortisone (HC) are proven teratogens that can negatively influence embryo development during early pregnancy. Proliferation of cells is one of the main developmental processes during the early embryogenesis. This study was focused on testing the effect of elevated temperature and HC addition on proliferation of cells in in vitro cultures. The V79-4 cell line was treated with HC and cultured in vitro at 37 °C or 39 °C, respectively. To reveal the effect of both factors, the proliferation of cells cultured under different conditions was evaluated using various approaches (colony formation assay, generation of growth curves, computation of doubling times, and mitotic index estimation). Our results indicate that a short-term exposure to elevated temperature slightly stimulates and a long-term exposure suppresses cell proliferation. However, HC (0.1 mg/ml) acts as a stimulator of cell proliferation. Interestingly, the interaction of HC and long-term elevated temperature (39 °C) exposure results in at least partial compensation of the negative impact of elevated temperature by HC addition and in higher proliferation if compared with cells cultured at 39 °C without addition of HC.

An augmented hybrid multibaseline and referenceless MR thermometry motion compensation algorithm for MRgHIFU hyperthermia.

PURPOSE: A hybrid principal component analysis and projection onto dipole fields (PCA-PDF) MR thermometry motion compensation algorithm was optimized with atlas image augmentation and validated. METHODS: Experiments were conducted on a 3T Philips MRI and Profound V1 Sonalleve high intensity focused ultrasound (high intensity focused ultrasound system. An MR-compatible robot was configured to induce motion on custom gelatin phantoms. Trials with periodic and sporadic motion were introduced on phantoms while hyperthermia was administered. The PCA-PDF algorithm was augmented with a predictive atlas to better compensate for larger sporadic motion. RESULTS: During periodic motion, the temperature SD in the thermometry was improved from 1 . 1 ± 0 . 1 $$ 1.1\pm 0.1 $$ to 0 . 5 ± 0 . 1 ∘ $$ 0.5\pm 0.{1}^{\circ } $$ C with both the original and augmented PCA-PDF application. For large sporadic motion, the augmented atlas improved the motion compensation from the original PCA-PDF correction from 8 . 8 ± 0 . 5 $$ 8.8\pm 0.5 $$ to 0 . 7 ± 0 . 1 ∘ $$ 0.7\pm 0.{1}^{\circ } $$ C. CONCLUSION: The PCA-PDF algorithm improved temperature accuracy to <1°C during periodic motion, but was not able to adequately address sporadic motion. By augmenting the PCA-PDF algorithm, temperature SD during large sporadic motion was also reduced to <1°C, greatly improving the original PCA-PDF algorithm.

Risk Factors for Admission Hyperthermia and Associated Outcomes in Infants Born Preterm.

Maternal, placental, and neonatal factors were compared between infants born at ≤29 weeks of gestational age with admission hyperthermia (>37.5○C) and euthermia (36.5-37.5○C). Admission hyperthermia was associated with longer duration of face-mask positive-pressure ventilation and infant's temperature ≥37.5○C in the delivery room. Infants born preterm with admission hyperthermia had greater odds of developing necrotizing enterocolitis and neurodevelopmental impairment.