ABSTRACT
The Curie temperature is an important thermo-characteristic of magnetic materials, which causes a phase transition from ferromagnetic to paramagnetic by changing the spontaneous re-arrangement of their spins (intrinsic magnetic mechanism) due to an increase in temperature. The self-control-temperature (SCT) leads to the conversion of ferro/ferrimagnetic materials to paramagnetic materials, which can extend the temperature-based applications of these materials from industrial nanotechnology to the biomedical field. In this case, magnetic induction hyperthermia (MIH) with self-control-temperature has been proposed as a physical thermo-therapeutic method for killing cancer tumors in a biologically safe environment. Specifically, the thermal source of MIH is magnetic nanoparticles (MNPs), and thus their biocompatibility and Curie temperature are two important properties, where the former is required for their clinical application, while the latter acts as a switch to automatically control the temperature of MIH. In this review, we focus on the Curie temperature of magnetic materials and provide a complete overview beginning with basic magnetism and its inevitable relation with Curie's law, theoretical prediction and experimental measurement of the Curie temperature. Furthermore, we discuss the significance, evolution from different types of alloys to ferrites and impact of the shape, size, and concentration of particles on the Curie temperature considering the proposed SCT-based MIH together with their biocompatibility. Also, we highlight the thermal efficiency of MNPs in destroying tumor cells and the significance of a low Curie temperature. Finally, the challenges, concluding remarks, and future perspectives in promoting self-control-temperature based MIH to clinical application are discussed.
Subject(s)
Hyperthermia, Induced , Neoplasms , Humans , Temperature , Hyperthermia, Induced/methods , Magnetics , Magnets , HyperthermiaABSTRACT
Magnetic sphincter augmentation (MSA) is an alternative surgical treatment for gastroesophageal reflux disease; however, >1.5 T magnetic resonance imaging (MRI) is contraindicated for patients who have undergone MSA with the LINX Reflux Management System (Torax Medical, Inc. Shoreview, Minnesota, USA). This drawback can impose a barrier to access of MRI, and cases of surgical removal of the device to enable patients to undergo MRI have been reported. To evaluate access to MRI for patients with an MSA device, we conducted a structured telephone interview with all diagnostic imaging providers in Arizona in 2022. In 2022, only 54 of 110 (49.1%) locations that provide MRI services had at least one 1.5 T or lower MRI scanner. The rapid replacement of 1.5 T MRI scanners by more advanced technology may limit healthcare options and create an access barrier for patients with an MSA device.
Subject(s)
Gastroesophageal Reflux , Laparoscopy , Humans , Esophageal Sphincter, Lower/surgery , Gastroesophageal Reflux/diagnostic imaging , Gastroesophageal Reflux/surgery , Fundoplication/methods , Magnets , Magnetic Resonance Imaging , Laparoscopy/methods , Treatment Outcome , Quality of LifeABSTRACT
The high prevalence of breast cancer and the high complication rate of combined radical treatment make the issue of medical rehabilitation using physical factors in patients after surgery highly relevant and warrant the need to determine the contribution of individual factors. OBJECTIVE: To compare the efficacy of general magnetic therapy and low-frequency electrostatic field on days 2-4 after the radical surgical treatment of breast cancer and 1.0-1.5 months after radiation therapy in combination with therapeutic physical training, motor-cognitive training, and sessions with a psychologist. MATERIALS AND METHODS: Examination and medical rehabilitation of 131 patients after radical surgical treatment of breast cancer were performed. Age ranged from 30 to 75 years. Group 1 included 66 patients who received medical rehabilitation on days 2-4 after the surgery and 1.0-1.5 months later in addition to adjuvant radiotherapy; Group 2 included 65 patients who received medical rehabilitation only after 1.0-1.5 months in addition to adjuvant radiotherapy. RESULTS AND CONCLUSION: It was shown that two courses of medical rehabilitation with the addition of physiotherapeutic treatment on days 2-4 and 1.0-1.5 months after radical breast cancer surgery in addition to radiation therapy contribute to a significant reduction of functional disorders severity in patients versus initiation of medical rehabilitation 1.0-1.5 months after the surgery in addition to radiation therapy. The feasibility of including general magnetic therapy procedures and low-frequency electrostatic field exposure in the medical rehabilitation course was demonstrated as it results in pain relief, postoperative edema reduction, and quicker recovery of the shoulder joint mobility that promotes long-term clinical benefit.
Subject(s)
Breast Neoplasms , Adult , Aged , Breast Neoplasms/surgery , Female , Humans , Magnets , Mastectomy , Middle Aged , Postoperative Period , Static ElectricityABSTRACT
Newer iPhone models with MagSafe magnetic technology can cause electromagnetic interference with the Inspire upper airway stimulator device (a surgical implant for the treatment of obstructive sleep apnea). Laryngoscope, 132:2513-2515, 2022.
Subject(s)
Electric Stimulation Therapy , Sleep Apnea, Obstructive , Humans , Hypoglossal Nerve/surgery , Magnets , Sleep Apnea, Obstructive/surgery , TechnologyABSTRACT
With the wide application of magnetic resonance imaging in hospitals and permanent magnets in household items, people have increased exposure to various types of static magnetic fields (SMFs) with moderate and high intensities, which has caused a considerable amount of public concern. Studies have shown that some aspects of gametogenesis and early embryonic development can be significantly affected by SMFs, while others have shown no effects. This review summarizes the experimental results of moderate to high-intensity SMFs (1 mT-16.7 T) on the reproductive development of different model animals, and we find that the effects of SMFs are variable depending on experimental conditions. In general, the effects of inhomogeneous SMFs seem to be more significant compared to that of homogeneous SMFs, which is likely due to magnetic forces generated by the magnetic field gradient. Moreover, some electromagnetic fields may have induced bioeffects because of nonnegligible gradient and heat effect, which are much reduced in superconducting magnets. We hope this review can provide a starting point for more in-depth analysis of various SMFs on reproduction, which is indispensable for evaluating the safety and potential applications of SMFs on living organisms in the future. © 2022 Bioelectromagnetics Society.
Subject(s)
Electromagnetic Fields , Magnetic Fields , Animals , Humans , Magnetic Resonance Imaging , Magnets , ReproductionABSTRACT
Migraine is a primary form of headache characterized by throbbing unilateral attacks, increased sensitivity to light and sound, accompanied by nausea and/or vomiting, lasting from 4 hours to 3 days. Developing and implementing new methods of pain relief is an urgent task of modern medicine. One of the safest and most commonly recommended methods is transcranial magnet therapy (TMT). OBJECTIVE: To evaluate the effect of TMT on improving the effectiveness of comprehensive therapy in patients with migraine. MATERIAL AND METHODS: A blind, randomized, placebo-controlled clinical trial was conducted, including 50 patients with migraine divided into three groups (the main group received TMT; the comparison group received low-frequency magnet therapy with a magnetic pulse duration of 250 µs; the control group received treatment with placebo device). The objectives were to study the TMT effect on reduction of the frequency and intensity of headache attacks, the severity of associated symptoms, reduction of medications use, including analgesics, in patients with migraine, as well as to evaluate the statistical difference in the effectiveness of magnetic therapy with different magnetic pulse ratio on all of the above parameters in study patients. RESULTS: According to the study data, a positive effect of TMT on the patients' condition was observed. After treatment, 76.9% of the patients in the main group had a reduction of headache intensity compared to the control group (35%) and a 47.8% decrease in analgesics use. In the main group, a reduction of nausea (73.3% of patients), acousticophobia (77.8% of patients), and photophobia (81.8% of patients) was noted. The HADS scale showed a 44.3% reduction in anxiety and depression in the main group. CONCLUSION: The clinical efficacy of TMT in patients with migraine has been demonstrated. In clinical practice, it is reasonable to use TMT to improve the treatment effectiveness in patients with migraine.
Subject(s)
Magnets , Migraine Disorders , Analgesics/therapeutic use , Double-Blind Method , Humans , Migraine Disorders/complications , Migraine Disorders/diagnosis , Migraine Disorders/therapy , Treatment OutcomeABSTRACT
One of the current health care problems is a menopausal syndrome (MS), a set of symptoms characterized by specific metabolic, neurological, autonomous, and psychosomatic changes. Many authors believe that one of the main methods of prevention and treatment of menopausal disorders is hormone replacement therapy, but there are many contraindications. Therefore, there is increasing interest in the development of non-medicinal therapy methods, in particular, physiotherapeutic treatment. OBJECTIVE: To study the effect of total cryotherapy alone and in combination with transcranial magnet therapy on the microcirculation state and psychological status in patients with MS. MATERIAL AND METHODS: The study included 62 female patients (mean age was 51±1.9 years). Thirty-five (56%) patients had mild menopausal syndrome and 27 (44%) moderate severity. All patients were divided into two clinically and functionally comparable groups by simple randomization: Group 1: 30 patients who received total cryotherapy (TCT); Group 2: 32 patients who received complex treatment including TCT and transcranial magnet therapy. The blood lipid spectrum was studied in all patients before and after the treatment course. The psychological examination was carried out using the well-being/activity/mood test (WAM). The microcirculation state was assessed by laser Doppler flowmetry (LDF). RESULTS: The majority of the patients had abnormalities in the lipid spectrum, decreased psychological adaptation, and worsened microcirculation indices (according to LDF data). After a treatment course, improvement in the lipid spectrum, LDF, and WAM test scores according to all scales was more pronounced in group 2 patients receiving complex therapy. CONCLUSION: The combined effect of total cryotherapy and transcranial magnet therapy had a more pronounced positive impact on the lipid spectrum, psychoemotional state, and microcirculatory processes in patients with menopausal syndrome compared with the total cryotherapy alone. It can be assumed that this complex will be effectively used in practical healthcare.
Subject(s)
Magnets , Perimenopause , Cryotherapy , Female , Humans , Laser-Doppler Flowmetry , Microcirculation , Middle AgedABSTRACT
OBJECTIVE: Our goal was to compile the most recent and accurate data on the side effects of proton pump inhibitors (PPI). We also compared the efficacy of PPI to the efficacy of different surgical options for acid reflux control. BACKGROUND: Proton pump inhibitors are the primary therapy for chronic control of gastroesophageal reflux disease (GERD), but newer studies demonstrate deleterious side effects. Collating this information and contrasting it with surgical therapy for GERD provides evidence for possible practice changes in treatment. METHODS: A literature search utilizing PubMed was performed evaluating for PPI and anti-reflux surgery (ARS), focusing on articles that reflected information regarding the usage and efficacy of symptom control of both PPI and ARS. Search terms included "ARS, fundoplication, MSA, acute interstitial nephritis, acute kidney injury, chronic kidney disease, meta-analysis, PPI, H2 blocker, cardiovascular risk, and gut dysbiosis." We evaluated 271 articles by title, abstract, and data for relevance and included 70. RESULTS: Long-term control of GERD with PPI may have a greater than expected side effect profile than initially thought. Surgical options may provide greater symptom control than PPI without the side effects of long-term medical therapy. CONCLUSIONS: Anti-reflux control can be safely achieved with either PPI or surgical options; however, the long-term side effects noted in the review such as increased risk of cardiovascular events, renal disease, and gut dysbiosis may suggest surgical anti-reflux control as a better long-term option.
Subject(s)
Gastroesophageal Reflux/drug therapy , Gastroesophageal Reflux/surgery , Proton Pump Inhibitors/adverse effects , Acute Kidney Injury/chemically induced , Dysbiosis/chemically induced , Fundoplication/methods , Hepatic Encephalopathy/chemically induced , Humans , Magnets , Myocardial Infarction/chemically induced , Nephritis, Interstitial/chemically induced , Proton Pump Inhibitors/therapeutic use , Renal Insufficiency, Chronic/chemically induced , Risk Assessment , Stroke/chemically inducedABSTRACT
OBJECTIVES: To characterise opinions about needing to undergo MRI within the population of current cochlear implant (CI) users. BACKGROUND: Magnetic resonance imaging (MRI) of CI users is often associated with severe discomfort and magnet displacement. METHODS: A global online survey of 310 CI users was conducted between 22nd July and 13th September 2020. RESULTS: Only 55% of respondents had been told whether their model of CI could undergo MRI. 31% of respondents considered MRI when deciding whether to receive a CI, and 28% when deciding which CI model to have. 64% reported concerns related to their CI if needing MRI compared to 29% reporting concerns unrelated to their CI. Willingness to undergo MRI reduced when considering magnet removal, splinting, bandaging, local anaesthesia, lasting discomfort, an inability to use their CI, or a reduction in image quality because of their CI. The single most influential factor was the possibility of damaging their CI (63%). 59% of respondents would consider minor surgery to upgrade their retaining magnet to one of a rotating design. DISCUSSION: These findings highlight the heterogeneity of CI users' opinions about MRI. CONCLUSION: We suggest several opportunities for improving the dissemination of current and accurate MRI-related information for CI users.
Subject(s)
Cochlear Implantation , Cochlear Implants , Anesthesia, Local , Humans , Magnetic Resonance Imaging/methods , MagnetsABSTRACT
Instrumental physiotherapeutic treatment using portable devices is optimal for patients with rheumatic diseases due to the devices' greater accessibility. However, there are still issues concerning the efficacy of physical factors generated by portable equipment in osteoarthritis (OA), mostly due to the limited evidence. OBJECTIVE: To study the efficacy and safety of long-term use of the portable magnet therapy device ALMAG+ (Almag Active) in knee OA (KOA). MATERIALS AND METHODS: A double-blind, randomized, placebo-controlled, prospective, 55-week clinical trial of the medical device was conducted. The study included patients with primary and secondary (associated with immunoinflammatory rheumatic diseases) KOA stages I-III according to Kellgren-Lawrence diagnosed using generally accepted criteria (R. Altman et al., 1986). Enrollment of patients with secondary KOA was allowed given that the remission or low disease activity was achieved. During the study patients had to receive steady drug therapy. No intra-articular injections of glucocorticosteroids, hyaluronic acid, PRP, and physiotherapy procedures for knees (electrotherapy, shockwave therapy, heat therapy, hydrotherapy, peloid therapy) were allowed three months or less before the enrollment and throughout the study. According to the approved protocol, 77 patients (mean age 52.73±12.97 years) from two research centers participated in the study: 32 (41.6%) were males, and 45 (58.4%) were females. Primary KOA occurred in 41 (52%) patients, 36 (46.8%) patients had secondary KOA (associated with rheumatoid arthritis, ankylosing spondylitis, Sjögren's disease, psoriatic arthritis, systemic lupus erythematosus, or diffuse scleroderma). All patients received NSAIDs as a concomitant therapy, 24.7% received diacerein, 28.6% received disease-modifying anti-rheumatic drugs, 2.6% received methylprednisolone up to 8 mg/day, and 9% received biologic therapy. After randomization, 40 (52%) patients received placebo treatments (Group 1) and 37 (48%) received active treatments (Group 2). Both groups were comparable in the main parameters. The proportion of smokers was higher in Group 2, but the difference was not statistically significant. During the 55-week follow-up, three courses of 18 daily home magnet therapy procedures each were performed. RESULTS: In both groups, starting from week 5 of the study, an improvement of pain on movement and at rest according to VAS compared to the baseline (p<0.01 at all assessment time points) was observed, which can be explained by a pronounced placebo effect, often observed in OA. The improvement of pain at rest was more prominent in Group 2 vs. Group 1 at Week 21 (p=0.038) and Week 55 (p=0.017) of the study, probably due to the anti-inflammatory effect. The overall WOMAC index score was also lower in Group 2 vs. Group 1 at Weeks 21 and 55 (p=0.03 at both time points). The mean articular cartilage thickness, determined by ultrasound, reduced in Group 1 and remained practically unchanged in Group 2 (p=0.011). No adverse events associated with the use of the ALMAG+ (Almag Active) device, according to the attending physician, and no exacerbations of immunoinflammatory rheumatic diseases during the study period were reported. CONCLUSION: The results of a double-blind, placebo-controlled study of magnet therapy using a portable device demonstrated analgesic, anti-inflammatory, and structure-modifying effects of this type of physiotherapeutic treatment. No adverse events and exacerbations of rheumatic diseases associated with the study treatment have been reported.
Subject(s)
Osteoarthritis, Knee , Adult , Aged , Double-Blind Method , Female , Humans , Magnets , Male , Middle Aged , Osteoarthritis, Knee/therapy , Prospective Studies , Treatment OutcomeABSTRACT
A molecularly imprinted polymer (MIP) with magnetic carbon nanotubes (MCNTs) as carrier was synthesized and used for the enrichment and determination of ferulic acid (FA) by high-performance liquid chromatography (HPLC). The morphology and structure of the FA magnetic carbon nanotubes-molecularly imprinted polymers (MCNTs@FA-MIPs) were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results demonstrated that the prepared MCNTs@FA-MIPs had excellent magnetic properties and uniform appearance. The adsorption properties of the novel MIP were studied by kinetic, and isothermal adsorption experiments. The results showed that the MCNTs@FA-MIPs exhibited relatively good uptake kinetics (equilibrium time, 2 h), high adsorption capacity (50 mgâ g-1), fast separation, and good selectivity for the template molecule with a separation factor α of 1.73. The MCNTs@FA-MIPs combined with HPLC were successfully applied to the separation, enrichment, and determination of FA in a Ligusticum chuanxiong extract and in plasma of rats which had been administered with Taitai beauty essence. The recoveries for FA were 95.53-100.03 % with relative standard deviations (RSDs) less than 5.5%. The results confirmed that the proposed MCNTs@FA-MIPs offered efficient extraction of FA from traditional Chinese medicinal preparations and blood samples and with high specificity.
Subject(s)
Chromatography, High Pressure Liquid/methods , Coumaric Acids/analysis , Coumaric Acids/isolation & purification , Molecularly Imprinted Polymers/chemistry , Nanotubes, Carbon/chemistry , Animals , Coumaric Acids/blood , Coumaric Acids/chemistry , Drugs, Chinese Herbal/chemistry , Linear Models , Magnets , Male , Rats, Sprague-Dawley , Reproducibility of Results , Sensitivity and Specificity , Solid Phase ExtractionABSTRACT
Secure long-term care units come with a unique set of challenges, particularly around exit-seeking behaviour. Arts-based environmental interventions on secure units successfully reduce problematic behaviours, while simultaneously ensuring resident safety and improving resident quality of life. The present arts-based project enhanced a distraction mural intervention to incorporate magnets as a participative arts feature. The project was evaluated through a roundtable discussion with unit staff. Findings showed that in addition to reducing exit-seeking behaviour, the magnets provided an aesthetically engaging set of objects for residents to gather up and hold, to pause and explore, and to create order. Challenges with direct care staff are identified and future ideas for arts-based projects on secure units are considered.
Subject(s)
Art Therapy , Behavior Therapy , Dementia/rehabilitation , Magnets , Aged , Female , Humans , Male , Quality of LifeABSTRACT
The efficient magnetic adsorbent (Fe3O4@ATP) was prepared by precipitation through the dispersion of Fe3O4 nanoparticles on the natural attapulgite (ATP) and then tested as an adsorbent for aflatoxin B1 (AFB1) removal from contaminated oils. The adsorbent characterization results revealed that the Fe3O4 were incorporated into the ATP, affording the Fe3O4@ATP composite. This magnetic composite displayed a good ability to eliminate AFB1 from contaminated oils with a removal efficiency of 86.82% using a 0.3% dosage. The Fe3O4@ATP possessed paramagnetic character with a saturation magnetization of 50.86 emu/g, enabling its easy separation from the medium using an external magnet. The adsorption process followed the pseudo-second-order model and fitted the Freundlich isotherm well. Moreover, the thermodynamic studies showed that AFB1 adsorption onto Fe3O4@ATP was exothermic and spontaneous. The novelty of this study lies in the fabrication of magnetic composite adsorbents for AFB1 elimination from oils.
Subject(s)
Aflatoxin B1/isolation & purification , Arachis/chemistry , Food Contamination , Magnesium Compounds/chemistry , Magnets/chemistry , Plant Oils/chemistry , Silicon Compounds/chemistry , Adsorption , Aflatoxin B1/chemistry , Kinetics , ThermodynamicsABSTRACT
AIM: In order to develop fundamentally new technologies for non-invasive and safer diagnosis of cancer, we aimed to detect non-contact magnetic signals from a malignant tumor in animals treated or not-treated with the ferromagnetic nanocomposite Ferroplat. MATERIALS AND METHODS: Guerin's carcinoma was used as a model of tumor growth. The biomagnetism of the tumor was evaluated in the dynamics of its growth. Ten days after tumor transplantation, Ferroplat was administered intravenously to half of the animals with the tumor and to half of the control animals. The magnitude of the magnetic signals was determined 1 h and every two days after administration of the nanocomposite using a Superconducting Quantum Interference Device magnetometer of the original design. RESULTS: We have found that the magnetic signals coming from the tumor are significantly higher compared to control tumor-free animals. Intravenous administration of a ferromagnetic nanocomposite (Ferroplat: Fe3O4 + cisplatinum) led to a significant increase of the magnetic signal, especially in the tumor tissue, and inhibition of Guerin's carcinoma growth. Ferromagnetic nanoparticles (32.7 nm) are retained in malignant cells for a longer time than in normal ones. CONCLUSION: Tumor cells accumulate iron nanoparticles more intensively than normal ones. Nanocomposite Ferroplat can be used for a targeted delivery of cisplatin to malignant cells.
Subject(s)
Biophysical Phenomena , Carcinoma/diagnosis , Magnets , Nanocomposites , Animals , Carcinoma/drug therapy , Cisplatin/chemistry , Female , Magnetometry/instrumentation , Magnetometry/methods , Magnetometry/standards , Neoplasms, Experimental , Radiation-Sensitizing Agents/chemistry , Rats , Signal-To-Noise RatioABSTRACT
Chemotherapy is one of the most commonly utilized approaches to treat malignant tumor. However, the well-controlled chemotherapy able to accurately manipulate local drugs for on-demand tumor treatment is still a challenge. Herein, a magnet and light dual-responsive hydrogel combining thermosensitive poly(N-acryloyl glycinamide) (PNAGA), doxorubicin (DOX) loaded and polyester (PE) capped mesoporous silica nanocarriers (MSNs) as well as Fe3O4 nanoparticles (Fe3O4 NPs) grafted graphene oxide (GO) was fabricated to address above issue. The Fe3O4 NPs and GO respectively serve as magnetothermal agent and photothermal agent to perform hyperthermia, meanwhile to generate chain motion of PNAGA with varying degrees under different conditions of magnetic field and/or NIR irradiation. This strategy not only allowed the gel-sol transition of the hydrogel by prior heating for tumor injection, but performed controllable release routes of DOX-MSNs-PE (DMP for short) nanocarriers to meet various requirements from different patients and the changing states of tumor. Furthermore, these escaped DMP nanocarriers could be taken by surrounding tumor cells, and then deliver their drug to these cells after rapid hydrolysis of the PE cap triggered by esterase, resulting in accurate chemotherapy. Both in vitro and in vivo results indicated that the PNAGA-DMP-Fe3O4@GO hydrogel combining well-controllable chemotherapy and hyperthermia can eliminate more than 90% tumor cells and effectively inhibit the tumor growth in mice model, demonstrating the great candidate of our hydrogel for accurate tumor therapy.
Subject(s)
Hyperthermia, Induced , Nanoparticles , Animals , Doxorubicin , Humans , Magnets , Mice , Nanogels , Silicon DioxideABSTRACT
Magnetic nanostructures and nanomaterials play essential roles in modern bio medicine and technology. Proper surface functionalization of nanoparticles (NPs) allows the selective bonding thus application of magnetic forces to a vast range of cellular structures and biomolecules. However, the spherical geometry of NPs poises a series of limitations in various potential applications. Mostly, typical spherical core shell structure consists of magnetic and non-magnetic layers have little tunability in terms of magnetic responses, and their single surface functionality also limits chemical activity and selectivity. In comparison to spherical NPs, nanowires (NWs) possess more degrees of freedom in achieving magnetic and surface chemical tenability. In addition to adjustment of magnetic anisotropy and inter-layer interactions, another important feature of NWs is their ability to combine diï¬erent components along their length, which can result in diverse bio-magnetic applications. Magnetic NWs have become the candidate material for biomedical applications owing to their high magnetization, cheapness and cost effective synthesis. With large magnetic moment, anisotropy, biocompatibility and low toxicity, magnetic NWs have been recently used in living cell manipulation, magnetic cell separation and magnetic hyperthermia. In this review, the basic concepts of magnetic characteristics of nanoscale objects and the influences of aspect ratio, composition and diameter on magnetic properties of NWs are addressed. Some underpinning physical principles of magnetic hyperthermia (MH), magnetic resonance imaging (MRI) and magnetic separation (MS) have been discussed. Finally, recent studies on magnetic NWs for the applications in MH, MRI and MS were discussed in detail.
Subject(s)
Hyperthermia, Induced/methods , Magnetic Resonance Imaging/methods , Magnets/analysis , Nanotechnology/methods , Nanowires/analysis , Animals , Contrast Media/analysis , Equipment Design , Humans , Hyperthermia, Induced/instrumentation , Magnetic Resonance Imaging/instrumentation , Magnetics/instrumentation , Magnetics/methods , Nanotechnology/instrumentation , Nanowires/ultrastructureABSTRACT
Human liver microsomes (HLM) are a commonly used tool to study drug metabolism in vitro. Typical experiments conducted using suspensions of HLM can be challenging to separate from the incubation solution without lengthy ultracentrifugation steps. Magnetizable beads coated with silica (MGBS) were found to bind strongly to HLM, which could then be isolated and purified using a magnet. Binding of HLM to the MGBS (HLM-MGBS) was demonstrated to be mediated by strong interactions between microsomal phospholipids and MGBS, as artificially prepared phosphatidylcholine (PC) liposomes could be more efficiently captured by the MGBS. HLM-MGBS complexes retained functional cytochrome P450 and uridine-diphosphate-glucuronosyltransferase (UGT) activity as indicated by CYP2C8-mediated amodiaquine de-ethylation, CYP3A4-mediated midazolam 1'hydroxylation, UGT1A1-mediated glucuronidation of estradiol, UGT1A9-mediated glucuronidation of propofol, and UGT2B7-mediated glucuronidation of zidovudine. When comparing suspension HLM alone with HLM-MGBS complexes containing equivalent amounts of HLM, the intrinsic clearance (CLint) of CYP450 substrates was comparable; however, CLint of UGT1A1, UGT1A9, and UGT2B7 was increased in the HLM-MGBS system between 1.5- and 6-fold. HLM-MGBS used in an incubation could also be readily replaced with fresh HLM-MGBS to maintain the presence of active enzymes. Thus, HLM-MGBS demonstrate increased in vitro metabolic efficiency and manipulability, providing a new platform for determination of accurate metabolic parameters. SIGNIFICANCE STATEMENT: The following work describes the strong binding of HLM to magnetizable beads. In addition, the preservation of enzyme activity on the bound HLM provides a novel means to conduct preclinical metabolism studies.
Subject(s)
Cell Culture Techniques/methods , Hepatobiliary Elimination , Cell Separation/methods , Cytochrome P-450 Enzyme System/metabolism , Drug Evaluation, Preclinical/methods , Enzyme Assays , Glucuronosyltransferase/metabolism , Humans , Magnets , Microsomes, Liver/metabolismABSTRACT
Hallucinogens induce the head-twitch response (HTR), a rapid reciprocal head movement, in mice. Although head twitches are usually identified by direct observation, they can also be assessed using a head-mounted magnet and a magnetometer. Procedures have been developed to automate the analysis of magnetometer recordings by detecting events that match the frequency, duration, and amplitude of the HTR. However, there is considerable variability in the features of head twitches, and behaviors such as jumping have similar characteristics, reducing the reliability of these methods. We have developed an automated method that can detect head twitches unambiguously, without relying on features in the amplitude-time domain. To detect the behavior, events are transformed into a visual representation in the time-frequency domain (a scalogram), deep features are extracted using the pretrained convolutional neural network (CNN) ResNet-50, and then the images are classified using a Support Vector Machine (SVM) algorithm. These procedures were used to analyze recordings from 237 mice containing 11,312 HTR. After transformation to scalograms, the multistage CNN-SVM approach detected 11,244 (99.4%) of the HTR. The procedures were insensitive to other behaviors, including jumping and seizures. Deep learning based on scalograms can be used to automate HTR detection with robust sensitivity and reliability.
Subject(s)
Behavior Observation Techniques/methods , Hallucinogens/pharmacology , Head Movements/drug effects , Support Vector Machine , Animals , Behavior Observation Techniques/instrumentation , Behavior, Animal/drug effects , Drug Evaluation, Preclinical/instrumentation , Drug Evaluation, Preclinical/methods , Magnetometry/instrumentation , Magnetometry/methods , Magnets , Male , Mice , Models, Animal , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Stroke is a disease affecting a large part of our society. According to WHO data, it is the second world's biggest killer, accounting for near six million deaths in 2016 and it is about 30% of the total number of strokes per year. Other patients affected by such a disease should be rehabilitated as soon as possible. As a result of this phenomenon, paresis may occur. Among the devices available on the market there are many rehabilitation robots, but the method of electrostimulation can be used. The authors focused their attention on electrostimulation and commercially available therapies. Using this method, application to people with large hand muscle contracture is difficult. The authors of the work present a solution dedicated to exactly such people. A solution of textronic sensors manufactured on a textile substrate using the technology of physical vapor deposition is presented in the article. As a result of the conducted research, an electroconductive structure was obtained with a low surface resistance value of 1 Ω/â¡ and high flexibility. It can alternatively be used in hand rehabilitation for electrostimulation of fingertips. The solution is dedicated to people with high hands spasticity for whom it is impossible to put on a rehabilitation glove.