Effect of duty cycles of tumor­treating fields on glioblastoma cells and normal brain organoids.

Tumor­treating fields (TTFields) are emerging cancer therapies based on alternating low­intensity electric fields that interfere with dividing cells and induce cancer cell apoptosis. However, to date, there is limited knowledge of their effects on normal cells, as well as the effects of different duty cycles on outcomes. The present study evaluated the effects of TTFields with different duty cycles on glioma spheroid cells and normal brain organoids. A customized TTFields system was developed to perform in vitro experiments with varying duty cycles. Three duty cycles were applied to three types of glioma spheroid cells and brain organoids. The efficacy and safety of the TTFields were evaluated by analyzing the cell cycle of glioma cells, and markers of neural stem cells (NSCs) and astrocytes in brain organoids. The application of the TTFields at the 75 and 100% duty cycle markedly inhibited the proliferation of the U87 and U373 compared with the control. FACS analysis revealed that the higher the duty cycle of the applied fields, the greater the increase in apoptosis detected. Exposure to a higher duty cycle resulted in a greater decrease in NSC markers and a greater increase in glial fibrillary acidic protein expression in normal brain organoids. These results suggest that TTFields at the 75 and 100% duty cycle induced cancer cell death, and that the neurotoxicity of the TTFields at 75% was less prominent than that at 100%. Although clinical studies with endpoints related to safety and efficacy need to be performed before this strategy may be adopted clinically, the findings of the present study provide meaningful evidence for the further advancement of TTFields in the treatment of various types of cancer.

Activation of Hair Cell Growth Factors by Linoleic Acid in Malva verticillata Seed.

Hair loss by excessive stress from work and lifestyle changes has become a growing concern, particularly among young individuals. However, most drugs for alopecia impose a plethora of side effects. We have found the powerful impact of Malva verticillata seed extracts on alleviating hair loss. This study further isolated effective chemicals in M. verticillata seed extracts by liquid silica gel column chromatography. Under the screening for the growth rate (%) of human follicles dermal papilla cells (HFDPCs), we identified linoleic acid (LA) and oleic acid in n-hexane of M. verticillate (MH)2 fraction. LA treatment activated Wnt/ß-catenin signaling and induced HFDPCs growth by increasing the expression of cell cycle proteins such as cyclin D1 and cyclin-dependent kinase 2. LA treatment also increased several growth factors, such as vascular endothelial growth factor, insulin-like growth factor-1, hepatocyte growth factor, and keratinocyte growth factor, in a dose-dependent manner. Besides, LA significantly inhibited Dickkopf-related protein expression (DKK-1), a primary alopecia signaling by dihydrotestosterone. Our findings suggest that LA treatment may alleviate a testosterone-induced signaling molecule and induces HFDPCs growth by activating Wnt/ß-catenin signaling.

An Efficient Noninvasive Neuromodulation Modality for Overactive Bladder Using Time Interfering Current Method.

OBJECTIVE: The present study aimed to evaluate a new tibial nerve stimulation (TNS) modality, which uses interferential currents, in terms of the stimulation electric field penetration efficiency into the body and physiological effectiveness. METHODS: In silico experiments were performed to analyze the penetration efficiency of proposed interferential current therapy (ICT). Based on this, we performed in vivo experiments to measure excitation threshold of ICT for the tibial nerve, which is related to stimulation field near the nerve. Regarding analysis of the physiological effectiveness, in vivo ICT-TNS was performed, and changes in bladder contraction frequency and voiding volume were measured. The penetration efficiency and physiological effectiveness of ICT were evaluated by comparison with those of conventional TNS using transcutaneous electrical nerve stimulation (TENS). RESULTS: Simulation results showed that ICT has high penetration efficiency, thereby generating stronger field than TENS. These results are consistent with the in vivo results that nerve excitation threshold of ICT is lower than that of TENS. Moreover, ICT-TNS decreased contraction frequency and increased voiding volume, and its performance was profound compared with that of TENS-TNS. CONCLUSION: The proposed ICT is more efficient in inducing the stimulation field near the tibial nerve placed deep inside the body compared with conventional TENS and shows a good clinical effectiveness for TNS. SIGNIFICANCE: The high efficiency of ICT increases the safety of noninvasive neurostimulation; therefore, it has clinical potential to become a promising modality for TNS to treat OAB and other peripheral neurostimulations.

The long-lasting post-stimulation inhibitory effects of bladder activity induced by posterior tibial nerve stimulation in unanesthetized rats.

Tibial nerve stimulation (TNS) is one of the neuromodulation methods used to treat an overactive bladder (OAB). However, the treatment mechanism is not accurately understood owing to significant differences in the results obtained from animal and clinical studies. Thus, this study was aimed to confirm the response of bladder activity to the different stimulation frequencies and to observe the duration of prolonged post-stimulation inhibitory effects following TNS. This study used unanesthetized rats to provide a closer approximation of the clinical setting and evaluated the changes in bladder activity in response to 30 min of TNS at different frequencies. Moreover, we observed the long-term changes of post-stimulation inhibitory effects. Our results showed that bladder response was immediately inhibited after 30 min of 10 Hz TNS, whereas it was excited at 50 Hz TNS. We also used the implantable stimulator to observe a change in duration of the prolonged post-stimulation inhibitory effects of the TNS and found large discrepancies in the time that the inhibitory effect lasted after stimulation between individual animals. This study provides important evidence that can be used to understand the neurophysiological mechanisms underlying the bladder inhibitory response induced by TNS as well as the long-lasting prolonged post-stimulation effect.

Long-Term Non Anesthetic Preclinical Study Available Extra-Cranial Brain Activator (ECBA) System for the Future Minimally Invasive Human Neuro Modulation.

In recent years, electroceuticals have been spotlighted as an emerging treatment for various severe chronic brain diseases, owing to their intrinsic advantage of electrical interaction with the brain, which is the most electrically active organ. However, the majority of research has verified only the short-term efficacy through acute studies in laboratory tests owing to the lack of a reliable miniaturized platform for long-term animal studies. The construction of a sufficient integrated system for such a platform is extremely difficult because it requires multi-disciplinary work using state-of-the-art technologies in a wide range of fields. In this study, we propose a complete system of an implantable platform for long-term preclinical brain studies. Our proposed system, the extra-cranial brain activator (ECBA), consists of a titanium-packaged implantable module and a helmet-type base station that powers the module wirelessly. The ECBA can also be controlled by a remote handheld device. Using the ECBA, we performed a long-term non-anesthetic study with multiple canine subjects, and the resulting PET-CT scans demonstrated remarkable enhancement in brain activity relating to memory and sensory skills. Furthermore, the histological analysis and high-temperature aging test confirmed the reliability of the system for up to 31 months. Hence, the proposed ECBA system is expected to lead a new paradigm of human neuromodulation studies in the near future.

Analyzing the advantages of subcutaneous over transcutaneous electrical stimulation for activating brainwaves.

Transcranial electrical stimulation (TES) is a widely accepted neuromodulation modality for treating brain disorders. However, its clinical efficacy is fundamentally limited due to the current shunting effect of the scalp and safety issues. A newer electrical stimulation technique called subcutaneous electrical stimulation (SES) promises to overcome the limitations of TES by applying currents directly at the site of the disorder through the skull. While SES seems promising, the electrophysiological effect of SES compared to TES is still unknown, thus limiting its broader application. Here we comprehensively analyze the SES and TES to demonstrate the effectiveness and advantages of SES. Beagles were bilaterally implanted with subdural strips for intracranial electroencephalography and electric field recording. For the intracerebral electric field prediction, we designed a 3D electromagnetic simulation framework and simulated TES and SES. In the beagle model, SES induces three to four-fold larger cerebral electric fields compared to TES, and significant changes in power ratio of brainwaves were observed only in SES. Our prediction framework suggests that the field penetration of SES would be several-fold larger than TES in human brains. These results demonstrate that the SES would significantly enhance the neuromodulatory effects compared to conventional TES and overcome the TES limitations.

Effectiveness of electrical stimulation on nerve regeneration after crush injury: Comparison between invasive and non-invasive stimulation.

Several studies have investigated the use of invasive and non-invasive stimulation methods to enhance nerve regeneration, and varying degrees of effectiveness have been reported. However, due to the use of different parameters in these studies, a fair comparison between the effectiveness of invasive and non-invasive stimulation methods is not possible. The present study compared the effectiveness of invasive and non-invasive stimulation using similar parameters. Eighteen Sprague Dawley rats were classified into three groups: the iES group stimulated with fully implantable device, the tES group stimulated with transcutaneous electrical nerve stimulation (TENS), and the injury group (no stimulation). The iES and tES groups received stimulation for 6 weeks starting immediately after the injury. Motor function was evaluated using the sciatic functional index (SFI) every week. The SFI values increased over time in all groups; faster and superior functional recovery was observed in the iES group than in the tES group. Histological evaluation of the nerve sections and gastrocnemius muscle sections were performed every other week. The axon diameter and muscle fiber area in the iES group were larger, and the g-ratio in the iES group was closer to 0.6 than those in the tES group. To assess the cause of the difference in efficiency, a 3D rat anatomical model was used to simulate the induced electric fields in each group. A significantly higher concentration and intensity around the sciatic nerve was observed in the iES group than in the tES group. Vector field distribution showed that the field was orthogonal to the sciatic nerve spread in the tES group, whereas it was parallel in the iES group; this suggested that the tES group was less effective in nerve stimulation. The results indicated that even though rats in the TENS group showed better recovery than those in the injury group, it cannot replace direct stimulation yet because rats stimulated with the invasive method showed faster recovery and superior outcomes. This was likely attributable to the greater concentration and parallel distribution of electric field with respect to target nerve.

7,8-Dimethoxycoumarin stimulates melanogenesis via MAPKs mediated MITF upregulation.

Background: Melanin in the skin is the defense against the harmful UV radiation, which is considered as one of the major risk factors for skin cancer. The compound 7,8-dimethoxycoumarin (DMC, C11H10O4), a natural coumarin molecule present in several medicinal plants, possesses antioxidant and anti-inflammatory activities. However, the mechanism underlying its effects on melanogenesis in melanocytes is unclear. Therefore, we investigated the effect of DMC on melanogenesis activation in B16F10 melanoma cells. Methods: We examined the cytotoxic range of DMC on B16F10 melanoma cells and increased effects of melanogenesis, and intracellular tyrosinase activity. In addition, regulation mechanisms were assessed by Western blot analysis. Results: The results showed that DMC significantly increased melanin content and tyrosinase activity in the cells without being cytotoxic. Furthermore, DMC stimulated the expression of tyrosinase, TRP-1, TRP-2, and MITF thereby activating melanin production and Akt phosphorylation was increased in the Akt signaling pathway. on the contrary, interfering with the phosphorylation of ERK in the MAPKs pathway. Conclusions: These results suggest that DMC may serve as a candidate for potential melanin-producing activator and anti-gray hair applications.

Antioxidant and anti-inflammatory effects of Lilium lancifolium bulbs extract.

Lilium lancifolium is native to Northeast Asia and its bulbs have been used for medicinal treatment. Moreover, Japan has been using L. lancifolium bulbs more actively as food ingredients than Korea. Therefore, this study was to investigate the characteristics of Korean L. lancifolium bulbs, with respect to food component and functionality. As a result of proximate composition analysis, L. lancifolium bulbs have an abundant carbohydrate content. HPLC analysis indicated p-coumaric acid and ferulic acid contents of Korean L. lancifolium extract were 1.14 ± 0.01, 1.46 ± 0.00 mg/g, but only p-coumaric acid was less detected in Japanese extract. Also, Korean L. lancifolium bulbs extract exhibited significant antioxidant effects, as evaluated with antioxidant activity and compound, than Japanese extract. Furthermore, Korean L. lancifolium bulbs extract significantly inhibited pro-inflammatory protein expressions through MyD88 dependent pathway. Therefore, these results suggested Korean L. lancifolium bulbs have the potential to being functional food ingredients. PRACTICAL APPLICATIONS: Lilium lancifolium is a perennial plant belonging to the Liliaceae family. The storage organ of L. lancifolium is surrounded by several fleshy nodes at the base of the stem, called the bulb, which has been used as food or medicine to treat pneumonia and bronchitis. L. lancifolium is widely found in countries of Northeast Asia, such as Korea, Japan, and China, and its bulbs have been studied for presence of bioactive compounds that have important functional activities. The bioactive compounds in the L. lancifolium bulbs may vary from region to region. In this study, the difference observed in the contents of different bioactive compounds and the efficacy of anti-inflammatory effects of L. lancifolium bulbs from different regions were consistent in this regard. As a comparative study of food materials by region, these L. lancifolium bulbs have the potential to be used as a food material for preventing inflammatory diseases.

Reversibly pH-responsive gold nanoparticles and their applications for photothermal cancer therapy.

Microenvironment responsive nanomaterials are attractive for therapeutic applications with regional specificity. Here we report pH responsive gold nanoparticles which are designed to aggregate in acidic condition similar to cancer environment and returned to its original disassembled states in a physiological pH. The pH responsive behavior of the particles is derived by change of electrostatic interaction among the particles where attraction and repulsion play a major role in low and high pH of the environment, respectively. Since different electrostatic interaction behavior of the particles in varied pH is induced not by irreversible chemical change but by simple protonation differences, the pH responsive process of assembly and disassembly is totally reversible. The low pH specific aggregation of gold nanoparticles resulted in red shift of plasmonic absorption peak and showed higher photothermal efficacy in acidic pH than in normal physiological pH. The low pH specific photothermal effect with long wave laser irradiation was directly applied to cancer specific photothermal therapy and resulted higher therapeutic effect for melanoma cancer cells than non-pH responsive gold nanoparticles.

Easy cuts, easy rebound: Drug expenditures with massive price cuts in Korea.

BACKGROUNDS: Since 2012, the Korean government has introduced 46.5% price cut for off-patent medicines in order to reign everescalating drug expenditure. This study sought to appraise the impact of the price cut measure (in the context of Korean National Health Insurance system). METHODS: We employed Korean National Health Insurance database from January 2007 until December 2016 for 120 month period. An interrupted time series analysis with segmented regression analysis was conducted to estimate the impact of price cut on overall drug spending. RESULTS: Drug spending significantly dropped with the price cut by 186.22 billlion Korean Won (KRW) (p < 0.0001) and the trend after the price cut has also significantly decreased by 1.33 billion KRW (p = 0.002). However, it was predicted that total expenditures showed an increasing trend and bounced back to the original level. Quantity prescribed had no significance with the price cut. Unit price had a substantial drop (ß = -41.68, p < 0.0001) with the price-cut, but the trend after the intervention has increased (ß = 0.16, p = 0.656) with no significance. CONCLUSIONS: Although the price cut has successfully countered the everescalating pharmaceutical expenditures in Korea, the impact was temporary. A lack of demand-side measures resulted in an ineffectiveness and unsustainability of policy effect. Thus, more aggressive demand-side measures should be introduced in the Korean context,and both the demand and supply-sides should be balanced.

Antimelanogenic Effects of Polygonum tinctorium Flower Extract from Traditional Jeju Fermentation via Upregulation of Extracellular Signal-Regulated Kinase and Protein Kinase B Activation.

This study was carried out to investigate the antimelanogenic effects of a Polygonum tinctorium flower extract obtained using red nuruk, a traditional Jeju barley-based fermentation starter. We also studied the mechanism of action of the P. tinctorium fermented flower extract (PTFFE) in mouse melanoma cells (B16F10). Cells were treated with various concentrations (62.5, 125 and 250 µg/mL) of PTFFE and the results showed that PTFFE significantly decreased the melanin content and tyrosinase activity without being cytotoxic. In addition, PTFFE strongly inhibited the expression of tyrosinase and tyrosinase-related protein 2 by decreasing the expression of the microphthalmia-associated transcription factor, as shown by a western blot assay. Furthermore, PTFFE inhibited melanogenesis via upregulation of the phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B, also known as AKT. We also used inhibitors such as PD98059 (a specific ERK inhibitor) or LY294002 (an AKT inhibitor) to determine whether the signaling pathways are involved. High-performance liquid chromatography fingerprinting showed the presence of a quercetin glucoside (isoquercitrin) and quercetin in PTFFE. To test the potential for PTFFE application as a cosmetic material, we also performed a primary skin irritation test on human skin. In this assay, PTFFE did not induce any adverse reactions at the treatment dose. Based on these results, we suggest that PTFFE may be considered a potential antimelanogenesis candidate for topical applications.

Anti-melanogenic effect of gomisin N from Schisandra chinensis (Turcz.) Baillon (Schisandraceae) in melanoma cells.

Overproduction and accumulation of melanin in the skin can lead to pigmentation disorders, such as freckles and melasma. Many researchers are studying the regulation of melanogenesis in the skin with the aim of developing whitening cosmetics. In this study, bioactivity-guided separation of the hexane fraction of Schisandra chinensis (Turcz.) Baillon extract yielded five major compounds, ß-chamigrenal, α-ylangenol, gomisin N, gomisin A, and schisandrin. The structures were identified by using 1H-NMR and 13C-NMR spectroscopy and comparing the spectral data with published data. Melanogenesis inhibitory activity assay in alpha-melanocyte-stimulating hormone (α-MSH)-induced B16F10 mouse melanoma cells revealed that gomisin N was the active component and significantly inhibited melanin synthesis in a concentration-dependent manner. Thus, we evaluated the mechanism underlying its anti-melanogenic effect. Gomisin N inhibited the expression of tyrosinase and microphthalmia-associated transcription factor (MITF) in B16F10 cells, while it did not affect cAMP response element binding protein (CREB) phosphorylation. Additionally, gomisin N activated AKT phosphorylation, which inhibits MITF expression. Thus, our results strongly suggest that the active compound, gomisin N, has potential for use in cosmetics to reduce hyperpigmentation.

Goserelin plus tamoxifen compared to chemotherapy followed by tamoxifen in premenopausal patients with early stage-, lymph node-negative breast cancer of luminal A subtype.

OBJECTIVES: To study the outcomes of adjuvant goserelin combined with tamoxifen (GosTam) compared to chemotherapy followed by tamoxifen (ChemTam) in premenopausal patients with early stage, luminal A breast cancer. METHODS: From 2008 until 2013, data were retrospectively collected for premenopausal patients who underwent surgery for invasive tumors that were ≤2.0 cm, node-negative, strongly positive for estrogen and progesterone receptors, HER-2-negative, and Ki-67 < 25%. The patients were divided into two groups according to adjuvant regimen, either GosTam or ChemTam. All patients who underwent different adjuvant regimens were excluded. RESULTS: In total, 235 patients underwent GosTam and 171 patients underwent ChemTam. There were significantly more patients younger than 40 years in the GosTam group (32% GosTam vs. 22% ChemTam, p = 0.031). Mean tumor size was significantly smaller (1.19 cm vs. 1.48 cm, p < 0.001), Ki-67 significantly lower (p = 0.049), and nuclear grade was low in a significant number of patients in the GosTam group (2% vs. 13%, p < 0.001). After a median follow-up of 51.3 months, there was no mortality in either group. There was no significant difference in 5-year disease-free survival (DFS) between the two groups even after univariate analysis considering age, tumor size, nuclear grade, and P53% (GosTam = 98.9% vs. ChemTam = 95.7%, HR = 0.404, 95% CI = [0.073, 2.222], p = 0.248). CONCLUSION: There was no difference between treatment groups, and neither chemotherapy nor ovarian suppression seemed to improve the outcome. Thus, tamoxifen alone might be a sufficient option for this low-risk patient population.

Fractional Laser-Assisted Topical Imiquimod 5% Cream Treatment for Recalcitrant Common Warts in Children: A Pilot Study.

BACKGROUND: Conventional treatments for warts like cryotherapy are limited by the pain during procedures, especially in pediatric patients. Imiquimod is a topical immune response modifier, but the thick stratum corneum of common warts prevents drug permeation through skin. OBJECTIVE: To evaluate the efficacy and safety of fractional laser/topical 5% imiquimod cream for the treatment of warts in children. METHODS: Eleven pediatric patients with multiple recalcitrant common warts were included. Lesions were treated using an ablative fractional 2,940-nm Er:YAG laser at 1- or 2-week interval. After each laser treatment session, imiquimod 5% cream was self-applied once daily 5 days a week. Response and adverse effects were assessed 2 weekly until complete clearance or up to maximum of 48 weeks. Pain during fractional laser was assessed using a visual analogue scale (0-10). RESULTS: Eight of the 11 (72.7%) children experienced complete clearance. Mean duration was 29.7 (16-48) weeks, and the mean number of fractional laser was 17.5 (8-37). No significant adverse effect was observed. Pain visual analogue scale during fractional laser was 2.4 (1-4) compared to 6.2 (5-8) during cryotherapy. CONCLUSION: This pilot study indicates that fractional laser-assisted topical imiquimod may provide benefit for recalcitrant warts in children.

Adverse events associated with acupuncture: a clinicopathologic review.

BACKGROUND: Acupuncture is one of the most popular modalities used to treat various diseases in traditional Korean and Oriental medicine. However, its risk of adverse events can be easily overlooked. OBJECTIVE: We investigated dermatological adverse events associated with acupuncture to draw attention to the risk of such adverse events. METHODS: We evaluated the types of acupuncture, clinicopathologic diagnoses, treatments, and prognoses in patients with a causal relationship between acupuncture and dermatoses. RESULTS: The study population comprised 25 patients (mean age, 52 years) with a history of acupuncture. Bee venom acupuncture was performed the most frequently (13 of 25 patients), and most patients received acupuncture to control pain (19 of 25 patients). The most common adverse event was infectious skin disease such as atypical mycobacterial infection or pyoderma/abscess, followed by hypersensitivity reactions, localized lipoatrophy, and hypertrophic scar. Acupuncture-related dermatoses required a relatively long treatment period (average, 8.6 weeks). CONCLUSION: Various dermatoses may occur following acupuncture. To minimize the risk of these dermatoses, proper training and medical knowledge in acupuncture practice are necessary for medical personnel. Dermatologists, oriental medical practitioners, and patients should pay attention to the potential adverse events of acupuncture.

Evaluation of the National Train-the-Trainer Program for Hospice and Palliative Care in Korea.

BACKGROUND: To evaluate the effectiveness of the National Train-the-Trainers Program for Hospice and Palliative Care Experts (TTHPC) sponsored by the National Cancer Center of Korea between 2009 and 2012. This program was developed to improve the teaching skills of those in the field of hospice and palliative care (HPC). MATERIALS AND METHODS: Training was offered in eight 1-day sessions between 2009 and 2012. The effect of the program was measured using Kirkpatrick's model of educational outcomes. First, levels 1 and 2 were evaluated immediately after the 1-day program (n=120). In 2012, the level-3 evaluation test was administered to trainers who offered at least one HPC training (n=78) as well as to their trainees (n=537). RESULTS: The level-1 evaluation addressed participant reactions to and satisfaction with the program. Participants (n=120) were generally satisfied with the content, the method, and the overall course (mean range: 3.94-4.46 on a five-point Likert scale). The level-2 evaluation (learning) showed that participants gained knowledge and confidence related to teaching HPC (4.24 vs. 4.00). The level-3 evaluation (behavioral), which assessed trainers' application of teaching skills to HPC, showed that trainees rated the teaching methods of trainers (mean range: 4.03-4.08) more positively than did trainers (p<0.05). Female trainers were more likely than were male trainers to plan sessions in consideration of their trainees' characteristics (4.11 vs. 3.58; p<0.05), and nurse trainers were more likely than physician trainers to use a variety of instructional methods (4.05 vs. 3.36; p<0.05) CONCLUSIONS: We conducted systematic evaluations based on Kirkpatrick's model to assess the effectiveness of our train-the- trainers program. Our educational program was practical, effective, and followed by our HPC experts, who needed guidance to learn and improve their clinical teaching skills.

Hypoxia-inducible factor directs POMC gene to mediate hypothalamic glucose sensing and energy balance regulation.

Hypoxia-inducible factor (HIF) is a nuclear transcription factor that responds to environmental and pathological hypoxia to induce metabolic adaptation, vascular growth, and cell survival. Here we found that HIF subunits and HIF2α in particular were normally expressed in the mediobasal hypothalamus of mice. Hypothalamic HIF was up-regulated by glucose to mediate the feeding control of hypothalamic glucose sensing. Two underlying molecular pathways were identified, including suppression of PHDs by glucose metabolites to prevent HIF2α degradation and the recruitment of AMPK and mTOR/S6K to regulate HIF2α protein synthesis. HIF activation was found to directly control the transcription of POMC gene. Genetic approach was then employed to develop conditional knockout mice with HIF inhibition in POMC neurons, revealing that HIF loss-of-function in POMC neurons impaired hypothalamic glucose sensing and caused energy imbalance to promote obesity development. The metabolic effects of HIF in hypothalamic POMC neurons were independent of leptin signaling or pituitary ACTH pathway. Hypothalamic gene delivery of HIF counteracted overeating and obesity under conditions of nutritional excess. In conclusion, HIF controls hypothalamic POMC gene to direct the central nutrient sensing in regulation of energy and body weight balance.

Implantable microstimulator: magnetic resonance safety at 1.5 Tesla.

RATIONALE AND OBJECTIVE: Ex vivo testing is necessary to characterize implants to determine if it is safe for the patient to undergo a magnetic resonance imaging (MRI) examination. Therefore, the objective of this study was to evaluate MR safety for an implantable microstimulator in association with a 1.5 Tesla MR system. METHODS: A microstimulator (RF BION, Alfred E. Mann Foundation for Scientific Research, Valencia, CA) was evaluated for magnetic field interactions and MRI-related heating. The functional aspects of this implant were assessed immediately before and after exposure to MRI (15 different pulse sequences). Artifacts were also characterized. RESULTS: Magnetic field interactions exhibited by the microstimulator will not pose a hazard after a suitable postimplantation period has elapsed. Temperature changes will not pose a risk. The function of the microstimulator was unaffected by MRI. Artifacts will only create a problem if the area of interest is in proximity to this implant (largest artifact area: T1-weighted spin echo, 2291 mm2; gradient echo, 3310 mm2). CONCLUSION: The overall findings indicated that it is safe for a patient with the microstimulator to undergo MRI at 1.5 Tesla by following specific safety guidelines described herein.