Citations
All
Search in:AllTitleAbstractAuthor name
Publications
(837)
Patents
Grants
Pathways
Clinical trials
Publication
Journal: Journal of Experimental Biology
July/20/1998
Abstract
The serotonergic Retzius neurons of the leech midbody ganglia respond in a complex manner to pressure pulses of acetylcholine (ACh) applied onto their soma with a fast depolarization followed by a slower hyperpolarization and an additional delayed long-lasting depolarization. The delayed depolarization is the subject of the present study. The delayed depolarization could be elicited by long (>1 s) ACh pressure pulses or by short pulses (10 ms) of carbachol, nicotine and DMPP, but not by muscarinic agonists. It was inhibited by bath application of nicotine (10-100 micromol l-1), strychnine (100 micromol l-1) and atropine (10-100 micromol l-1). Nicotinic antagonists that blocked the fast depolarization and the slow hyperpolarization (100 micromol l-1 mecamylamine and d-tubocurarine) did not affect the delayed depolarization induced by carbachol. Partial replacement of the extracellular Na+ by glucamine caused a decrease in the amplitude of the response and a shift of its reversal potential to more negative values. Carbachol pulses applied to Retzius neurons of the ganglia innervating the reproductive segments elicited delayed depolarizations of much smaller amplitude than the ones recorded in Retzius neurons from standard segments. The delayed depolarization could be elicited by the application of short agonist pulses onto different loci over the surface of the ganglion, at a distance from the soma. Isolated cultured Retzius neurons did not exhibit the delayed depolarization although they readily expressed the earlier phases of the complex cholinergic response. Carbachol pulses applied to the soma of other neurons in the leech ganglion produced a variety of specific responses.The results suggest that the delayed depolarization was produced by the activation of a cationic conductance mediated by receptors with a pharmacological profile similar to that of the <IMG src="/images/symbols/&agr ;.<em>gif</em>" WIDTH="9" HEIGHT= "12" ALIGN="BOTTOM" NATURALSIZEFLAG="3">9 nicotinic receptors and was not a byproduct of the early phases of the cholinergic response. The response seemed to be initiated in the extensive neuropilar processes of the Retzius cell, enabling a persistent excitatory signal.
Publication
Journal: Brain Research
June/20/2000
Abstract
Metallothionein (MT)-III, originally discovered as a growth inhibitory factor (GIF), is a brain specific isomer of MTs and is markedly reduced in the brain of patients with Alzheimer's disease (AD) or other neurodegenerative diseases. We analyzed the level and regulation of mRNA expression of MT-III in immortalized fetal mouse brain glial cells (VR-2g) by reverse transcriptase-polymerase chain reaction (RT-PCR). We have recently reported that dopamine (DA) increases the expression of MT-III mRNA in vitro. In this study, we investigated the mechanism of such increase by examining the effects of DA agonists (SKF38393 or bromocriptine) and DA antagonists (SCH23390 or sulpiride) on the expression of MT-III mRNA. MT-III mRNA did not change by either agonist and DA-increased MT-III mRNA was not inhibited by either antagonist. These results suggested that the induction of MT-III mRNA by DA was not mediated by stimulation of DA receptors. On the other hand, DA-induced MT-III mRNA expression was strongly inhibited by the addition of antioxidants (glutathione, vitamin E or ascorbic acid), indicating that DA-enhanced MT-III mRNA was mediated by reactive oxygen species. Our results suggest that oxidative stress may be one of the principle factors that modulate MT-III mRNA expression.
Publication
Journal: Annales de la Societe belge de medecine tropicale
July/9/1973
Publication
Journal: Endoscopy international open
December/12/2019
Abstract
Background and study aims The repair costs of gastrointestinal endoscopes account for a significant proportion of the total budget of an endoscopy unit. This study evaluated the repair costs of small-caliber endoscopes and conventional endoscopes used in esophagogastroduodenoscopy (EGD). Patients and methods A retrospective analysis of upper gastrointestinal endoscope damage and repair costs between April 2012 and May 2019 was performed at the Toyoshima Endoscopy Clinic. Conventional endoscopes (GIF-H260, GIF-HQ290, and GIF-H290Z) were used for transoral EGD while small-caliber endoscopes (GIF-XP260N and GIF-XP290N) were used for transnasal or transoral EGD. Results Three small-caliber endoscopes and five conventional endoscopes were used for 1,031 procedures and 31,192 procedures, respectively. The number of procedures/damage incidence for small-caliber endoscope and conventional endoscopes was 344 and 1950, respectively. Damage incidence for small-caliber endoscopes was significantly higher than for conventional endoscopes ( P = 0.014). Repair costs/procedure were $ 5.95 ± $132 for small-caliber endoscopes and $2.41 ± $115 for conventional endoscopes. Repair costs/procedure for small-caliber endoscopes were more than twice those for conventional endoscopes. Conclusions Small-caliber endoscopes are more fragile than conventional endoscopes.
Publication
Journal: Acta Ophthalmologica
February/11/1979
Abstract
The innervation of the rabbit conjunctiva was investigated histochemically. Nerves containing acetylcholinesterase (AChE) were demonstrated using a copper thiocholine technique. Sympathetic nerve fibres were demonstrated using either the formaldehyde-induced fluorescence (FIF) or glyoxylic acid induced fluorescence (GIF) method. In addition, GIF and AChE-reactions were performed consecutively for the demonstration of fluorescent and AChE-positive nerves in the same specimen. The number of AChE-positive nerve fibres exceeded that of fluorescent fibres. Both fibre types were more numerous in the stroma of the limbal and tarsal conjunctiva than in the fornix. In the epithelium, only a few AChE-positive nerves were observed. These are assumed to be sensory. Most nerves seemed to contain both catecholamine-containing and AChE-positive fibres. However, nerves fibres containing only AChE-activity were also found. The blood vessels of the conjunctiva were innervated by both fluorescent and AChE-positive nerves, the distribution and number of which differed slightly.
Publication
Journal: Acta Gastro-Enterologica Belgica
January/17/2020
Abstract
To identify computed tomography (CT) features that predict gastrointestinal fistula (GIF) in patients with acute pancreatitis (AP).This retrospective study comprised consecutive patients with AP and GIF from June 2017 to June 2018. The diagnosis of GIF was based on upper gastrointestinal endoscopy, colonoscopy or surgery. A cohort of 19 matched patients from a prospective database of AP served as control group. Measures of severity, and clinical outcome were evaluated. CT parameters were compared between the groups to assess the features that could predict the development of GIF.There was no difference between the two groups in terms of disease etiology, severity, drainage, and mortality. On univariate analysis, the CT features that were found to be significantly different between the two groups were the presence of bowel wall thickening (P=0.005), maximum thickness of the bowel wall (P=0.007), presence of air foci in extra pancreatic necrosis/ collection (P=0.013), discontinuity of the bowel wall (P=0.046) and the displacement/ compression of bowel by fluid collection (P=0.014). On multivariate analysis, all the above-mentioned CT findings except discontinuity of bowel wall were found to be statistically significant.CT is helpful in predicting GIF in patients with AP.
Publication
Journal: Journal of Neurology, Neurosurgery and Psychiatry
January/22/2021
Abstract
Objective: To identify subgroups of former National Football League (NFL) players using latent profile analysis (LPA) and examine their associations with total years of participation (TYP) and self-reported lifetime sport-related concussion history (SR-CHx).
Methods: Former NFL players (N=686) aged 50-70 years, with an average 18.0 TYP (±4.5) completed a questionnaire. SR-CHx distributions included: low (0-3; n=221); intermediate (4-8; n=209) and high (9+; n=256). LPA measures included: Quality of Life in Neurological Disorders Emotional-Behavioral Dyscontrol, Patient Reported Outcomes Measurement Information System Cognitive Function, Emotional Support, Self-Efficacy, Meaning and Purpose, Physical Function, Pain Interference, Participation in Social Roles and Activities, Anxiety, Depression, Fatigue, and Sleep Disturbance. Demographic, medical/psychiatric history, current psychosocial stressors, TYP and SR-CHx were compared across latent profiles (LPs).
Results: A five profile solution emerged: (LP1) global higher functioning (GHF; 26.5%); (LP2) average functioning (10.2%); (LP3) mild somatic (pain and physical functioning) concerns (22.0%); (LP4) somatic and cognitive difficulties with mild anxiety (SCA; 27.5%); LP5) global impaired functioning (GIF; 13.8%). The GIF and SCA groups reported the largest number ofe- medical/psychiatric conditions and higher psychosocial stressor levels. SR-CHx was associated with profile group (χ2(8)=100.38, p<0.001); with a higher proportion of GIF (72.6%) and SCA (43.1%) groups reporting being in the high SR-CHx category, compared with GHF (23.1%), average (31.4%) and somatic (27.8%) groups. TYP was not significantly associated with group (p=0.06), with greater TYP reported by the GHF group.
Conclusions: Five distinct profiles of self-reported functioning were identified among former NFL players. Several comorbid factors (ie, medical/psychiatric diagnoses and psychosocial stressors) and SR-CHx were associated with greater neurobehavioural and psychosocial dysfunction.
Publication
Journal: Brain Research
April/24/2005
Abstract
We investigate the aging effects of the hyperoxia-mediated induction of two antioxidants and three antioxidant enzymes in the rat brain. All of these genes responded to hyperoxia in young but not aged brains. Despite the partial inactivation of CuZn SOD and glutathione peroxidase by hyperoxia in aged rat brains, lipid peroxidation did not increase. The higher growth inhibitory factor (GIF) content in aged rat brains may be utilized as an antioxidant during hyperoxia.
Publication
Journal: Genome Biology and Evolution
September/27/2015
Abstract
The uptake and transport of vitamin B12 (cobalamin; Cbl) in mammals involves a refined system with three evolutionarily related transporters: transcobalamin 1 (Tcn1), transcobalamin 2 (Tcn2), and the gastric intrinsic factor (Gif). Teleosts have a single documented binder with intermediate features to the human counterparts. Consequently, it has been proposed that the expansion of Cbl binders occurred after the separation of Actinopterygians. Here, we demonstrate that the diversification of this gene family took place earlier in gnathostome ancestry. Our data indicates the presence of single copy orthologs of the Sarcopterygii/Tetrapoda duplicates Tcn1 and Gif, and Tcn2, in Chondrichthyes. In addition, a highly divergent Cbl binder was found in the Elasmobranchii. We unveil a complex scenario forged by genome, tandem duplications and lineage-specific gene loss. Our findings suggest that from an ancestral transporter, exhibiting large spectrum and high affinity binding, highly specific Cbl transporters emerged through gene duplication and mutations at the binding pocket.
Publication
Journal: JMIR Research Protocols
November/15/2018
Abstract
BACKGROUND
Substance use is an alarming public health issue associated with significant morbidity and mortality. Adolescents and emerging adults are at particularly high risk because substance use typically initiates and peaks during this developmental period. Mobile health apps are a promising data collection and intervention delivery tool for substance-using youth as most teens and young adults own a mobile phone. However, engagement with data collection for most mobile health applications is low, and often, large fractions of users stop providing data after a week of use.
OBJECTIVE
Substance Abuse Research Assistant (SARA) is a mobile application to increase or sustain engagement of substance data collection overtime. SARA provides a variety of engagement strategies to incentivize data collection: a virtual aquarium in the app grows with fish and aquatic resources; occasionally, funny or inspirational contents (eg, memes or text messages) are provided to generate positive emotions. We plan to assess the efficacy of SARA's engagement strategies over time by conducting a micro-randomized trial, where the engagement strategies will be sequentially manipulated.
METHODS
We aim to recruit participants (aged 14-24 years), who report any binge drinking or marijuana use in the past month. Participants are instructed to use SARA for 1 month. During this period, participants are asked to complete one survey and two active tasks every day between 6 pm and midnight. Through the survey, we assess participants' daily mood, stress levels, loneliness, and hopefulness, while through the active tasks, we measure reaction time and spatial memory. To incentivize and support the data collection, a variety of engagement strategies are used. First, predata collection strategies include the following: (1) at 4 pm, a push notification may be issued with an inspirational message from a contemporary celebrity; or (2) at 6 pm, a push notification may be issued reminding about data collection and incentives. Second, postdata collection strategies include various rewards such as points which can be used to grow a virtual aquarium with fishes and other treasures and modest monetary rewards (up to US $12; US $1 for each 3-day streak); also, participants may receive funny or inspirational content as memes or gifs or visualizations of prior data. During the study, the participants will be randomized every day to receive different engagement strategies. In the primary analysis, we will assess whether issuing 4 pm push-notifications or memes or gifs, respectively, increases self-reporting on the current or the following day.
RESULTS
The microrandomized trial started on August 21, 2017 and the trial ended on February 28, 2018. Seventy-three participants were recruited. Data analysis is currently underway.
CONCLUSIONS
To the best of our knowledge, SARA is the first mobile phone app that systematically manipulates engagement strategies in order to identify the best sequence of strategies that keep participants engaged in data collection. Once the optimal strategies to collect data are identified, future versions of SARA will use this data to provide just-in-time adaptive interventions to reduce substance use among youth.
BACKGROUND
ClinicalTrials.gov NCT03255317; https://clinicaltrials.gov/show/NCT03255317 (Archived by WebCite at http://www.webcitation.org/70raGWV0e).
UNASSIGNED
RR1-10.2196/9850.
Publication
Journal: European Biophysics Journal
March/31/2021
Abstract
Biophysical quantification of protein interactions is central to unveil the molecular mechanisms of cellular processes. Researchers can choose from a wide panel of biophysical methods that quantify molecular interactions in different ways, including both classical and more novel techniques. We report the outcome of an ARBRE-MOBIEU training school held in June 2019 in Gif-sur-Yvette, France ( https://mosbio.sciencesconf.org/ ). Twenty European students benefited from a week's training with theoretical and practical sessions in six complementary approaches: (1) analytical ultracentrifugation with or without a fluorescence detector system (AUC-FDS), (2) isothermal titration calorimetry (ITC), (3) size exclusion chromatography coupled to multi-angle light scattering (SEC-MALS), (4) bio-layer interferometry (BLI), (5) microscale thermophoresis (MST) and, (6) switchSENSE. They implemented all these methods on two examples of macromolecular interactions with nanomolar affinity: first, a protein-protein interaction between an artificial alphaRep binder, and its target protein, also an alphaRep; second, a protein-DNA interaction between a DNA repair complex, Ku70/Ku80 (hereafter called Ku), and its cognate DNA ligand. We report the approaches used to analyze the two systems under study and thereby showcase application of each of the six techniques. The workshop provided students with improved understanding of the advantages and limitations of different methods, enabling future choices concerning approaches that are most relevant or informative for specific kinds of sample and interaction.
Keywords: Artificial binders; Double-stranded DNA breaks repair factors; Macromolecular interactions; Molecular scale biophysics.
Publication
Journal: Neuro-Oncology
October/9/2017
Abstract
UNASSIGNED
Meningiomas are common intracranial tumors in adults, yet the genetics and cause of sporadic meningiomas are not well understood. Few familial clusters have been reported. The aim of this study was to investigate the familiality of meningiomas within the Utah Population Database.
UNASSIGNED
Meningioma cases reported in the Utah Cancer Registry were identified. Relative risk of their relatives was calculated. All possible cases were assessed with the Genealogical Index of Familiality (GIF), which measures average pairwise relatedness of all possible pairs using the Malecot coefficient of kinship. Clusters of cases descending from a common ancestor were identified.
UNASSIGNED
Eight hundred fifty-eight meningioma cases were reported. The relative risk of a first- or second-degree relative was 3.13 (95% CI: 1.67, 5.36) or 2.28 (1.30, 3.70), respectively. The GIF statistic demonstrated a clear excess of relationships for genetic distance <4 (closer than first cousins). We identified 920 pedigrees, including 2-21 meningioma cases. One hundred eighty-nine of these pedigrees, including 2-15 cases, had a significant excess (P < 0.05) of meningioma cases over what was expected.
UNASSIGNED
This Utah population-based analysis of meningiomas shows clear evidence of familial clustering and supports both a familial and a germline variant basis for meningioma. These clusters may allow identification of genes likely to contribute to tumorigenesis in high-risk pedigrees. These relative risk data provide the basis for further investigations of genetic contributions to meningioma. These data may contribute to developing a basis for determining screening criteria of higher-risk pedigrees for the presence of meningiomas.
Publication
Journal: Journal of Medical Internet Research
January/10/2021
Abstract
Background: A diverse array of digital technologies are available to children and young people living in the Global North to monitor, manage, and promote their health and well-being.
Objective: This article provides a narrative literature review of the growing number of social research studies published over the past decade that investigate the types of digital technologies used by children and young people in the Global North, in addition to investigating which of these technologies they find most useful or not useful. Key findings as well as major gaps and directions for future research are identified and discussed.
Methods: A comprehensive search of relevant publications listed in Google Scholar was conducted, supported by following citation trails of these publications. The findings are listed under type of digital technology used for health: cross-media, internet, social media, apps and wearable devices, sexual health support and information, and mental health support and information.
Results: Many young people in the Global North are active users of digital health technologies. However, it is notable that they still rely on older technologies, such as websites and search engines, to find information. Apps and platforms that may not have been specifically developed for young people as digital health resources often better suit their needs. Young people appreciate the ready availability of information online, the opportunities to learn more about their bodies and health states, and the opportunities to learn how to improve their health and physical fitness. They enjoy being able to connect with peers, and they find emotional support and relief from distress by using social media platforms, YouTube, and online forums. Young people can find the vast reams of information available to them difficult to navigate. They often look to trusted adults to help them make sense of the information they find online and to provide alternative sources of information and support. Face-to-face interactions with these trusted providers remain important to young people. Risks and harms that young people report from digital health use include becoming overly obsessed with their bodies' shape and size when using self-tracking technologies and comparing their bodies with the social media influencers they follow.
Conclusions: Further details on how young people are using social media platforms and YouTube as health support resources and for peer-to-peer sharing of information, including attention paid to the content of these resources and the role played by young social media influencers and microcelebrities, would contribute important insights to this body of literature. The role played by visual media, such as GIFs (Graphics Interchange Format) and memes, and social media platforms that have recently become very popular with young people (eg, Snapchat and TikTok) in health-related content creation and sharing requires more attention by social researchers seeking to better understand young people's use of digital devices and software for health and fitness.
Keywords: Global North; digital health; narrative review; social research; young people.
Publication
Journal: Optics Letters
May/15/2019
Abstract
A highly sensitive temperature sensor is proposed and demonstrated based on a UV-curable polymer-infiltrated Mach-Zehnder interferometer (MZI) created in a graded index fiber (GIF). The device was constructed by splicing a half-pitch GIF between two single-mode fibers and creating an inner air cavity in one lateral side of the GIF core by means of femtosecond laser micromachining. The air cavity and the residual GIF core functioned as two interference arms of the MZI. Moreover, the GIF was used as a miniature in-fiber collimator to reduce insertion loss of the air cavity. Experimental results show such an MZI device has a high refractive index (RI) sensitivity of 24611.54 nm/RIU (RI=1.545-1.565). Subsequently, thermo-sensitive polymer liquid was infiltrated into the air cavity, then cured with UV illumination, and annealed at 50°C for 12 h. The infiltrated MZI exhibits a high temperature sensitivity of -13.27 nm/°C. In addition, this MZI also has excellent thermal stability and repeatability, compact structure, low insertion loss, and high fringe visibility. As such, the proposed MZI could be developed for high-accuracy temperature measurements in many areas such as biomedical or oceanographic applications.
Publication
Journal: European Journal of Pharmacology
January/27/2021
Abstract
Glutathione (GSH), which is particularly important for antioxidant defenses, is synthesized in two sequential enzymatic reactions catalyzed by γ-glutamylcysteine ligase (GCL) and GSH synthase. GCL comprises catalytic (GCLC) and regulatory subunits and catalyzes the rate-limiting step in de novo GSH synthesis. Accumulating evidence suggests that substances that stimulate GSH synthesis are therapeutic modalities for neurodegenerative disorders and schizophrenia, in which a deficit in brain GSH content has been observed. In the present study, we attempted to develop small organic compounds that increase GCLC transcription. Using HT22 cells stably expressing a luciferase reporter that contains rat GCLC promoter region (-1764 to +2), we assessed the effects of the novel neuroprotective compound oxindole and related compounds on GCLC promoter activity. Among approximately 220 synthesized compounds, five compounds increased GCLC promoter activity by >200% at a concentration of 50 μM, and 16 compounds increased promoter activity by approximately 150%. The most effective compound oxindole-curcumin hybrid GIF-2165X-G1 increased GCLC mRNA levels in HT22 mouse hippocampal cells, PC12 rat pheochromocytoma cells, and C6 rat glioma cells. Although GIF-2165X-G1 potently induced antioxidant response element (ARE)-driven transcription, the compound increased GCLC transcriptional activity through Sp1 pathway in a Keap1-Nrf2-ARE-independent manner. These results suggest that GIF-2165X-G1 itself and further modification of the compound are useful interventions for promoting neuronal survival by augmenting resistance to oxidative stress.
Keywords: HT22 cells; glutathione; oxindole; oxytosis/ferroptosis; γ-glutamylcysteine ligase.
Publication
Journal: AIDS
November/7/2018
Abstract
OBJECTIVE
Social media messages have been increasingly used in health campaigns about prevention, testing, and treatment of HIV. We identified factors leading to the retransmission of messages from expert social media accounts to create data-driven recommendations for online HIV messaging.
METHODS
We sampled 20 201 HIV-related tweets (posted between 2010 and 2017) from 37 HIV experts. Potential predictors of retransmission were identified based on prior literature and machine learning methods, and were subsequently analyzed using multilevel negative binomial models.
RESULTS
Fear-related language, longer messages, and including images (e.g. photos, gif, or videos) were the strongest predictors of retweet counts. These findings were similar for messages authored by HIV experts, and also messages retransmitted by experts, but created by nonexperts (e.g. celebrities or politicians).
CONCLUSIONS
Fear appeals affect how much HIV messages spread on Twitter, as do structural characteristics, like the length of the tweet and inclusion of images. A set of five data-driven recommendations for increasing message spread is derived and discussed in the context of current centers for disease control and prevention social media guidelines.
Publication
Journal: Cureus
July/31/2019
Abstract
Introduction One of the common causes of chronic sinusitis is a fungal infection, and there are various types of fungal rhinosinusitis (FRS). Missed diagnosis of occasional granulomatous invasion of fungal sinusitis can lead to involvement in the central nervous system. The aim of this study is to determine the frequency of granulomatous invasive fungal sinusitis (GIFS) in patients with clinical suspicion of chronic FRS. Methods We conducted a descriptive cross-sectional study in the Department of Ear, Nose and Throat (ENT), Nishtar Hospital, Multan from January 1, 2017 to July 1, 2018. Eighty-one patients with chronic FRS participated in the study. After informed consent, nasal tissue was biopsied for granulomatous fungal invasion. Results The frequency of GIFS was 29.6% (n=24) in this study. The significant risk factors included duration of chronic FRS for more than 12 weeks, history of diabetes mellitus, and living status as rural. Conclusion GIFS is a common complication in patients with clinical suspicion of chronic FRS. Nasal biopsy should be a common practice among patients of chronic FRS who have a long duration of disease and a history of diabetes mellitus.
Publication
Journal: Endoscopy
April/18/2021
Abstract
Background and study aims Endoscopic submucosal dissection (ESD) is widely performed for superficial esophageal cancer, but stricture after extensive resection is a major clinical problem. Using an ultrathin endoscope would enable endoscopists to approach lesions beyond the stricture. We evaluated the feasibility of an ultrathin endoscope for esophageal ESD. Methods To perform ESD with an ultrathin endoscope, we developed a transparent hood and ESD knife. A total of 24 esophageal ESDs were performed by two endoscopists with excised and live porcine esophaguses. A GIF-Q260 J and Dual knife were used in the conventional group and the GIF-XP260NS and a newly developed knife were used in the ultrathin group. En bloc resection rates, perforation rates, and procedure times were compared. Results All 24 lesions were resected en bloc without perforation. The mean procedure time was longer in the ultrathin group, although not significantly so (274.3 ± 81.8 s vs 435.8 ± 313.9 s, respectively; P = 0.22). Conclusion Although the procedure time was longer in the ultrathin group, en bloc resection was performed without any perforation. The findings indicate that esophageal ESD with an ultrathin endoscope is feasible.
Publication
Journal: Journal of Cellular Biochemistry
January/21/2021
Abstract
Tyrosinase catalyzes the rate-limiting step in melanin synthesis. Melanin is synthesized from l-tyrosin in the melanosomes, where tyrosinase and other melanogenic factors are recruited via the vesicle transport system. Genetic and biochemical approaches have revealed a correlation between impairments in the vesicle transport system and albinism. However, the specificity of the individual transport systems for the corresponding melanogenic factors has not been well elucidated yet. Here, we report that the thioxothiazolidin derivative, 4-OST (4-[(5E)-5-[(4-fluorophenyl)methylidene]-4-oxo-2-sulfanylidene-1,3-thiazolidin-3-yl]-4-azatricyclo [5.2.1.02 ,6]dec-8-ene-3,5-dione: CAS RN. 477766-87-3) strongly inhibited melanogenesis in mouse melanoma B16F10 cells. 4-OST reduces tyrosinase protein levels without affecting its messenger RNA levels or enzymatic activity. Although a reduction in tyrosinase protein level was observed in the presence of a protein synthesis inhibitor, the reduction may be coupled with protein synthesis. Similarly, GIF-2202 (a derivative of 4-OST) lowers tyrosinase protein levels without affecting the levels of another melanogenic enzyme, tyrosinase-related protein 1 (TYRP1) level. The reduction in tyrosinase protein level is associated with an increase in the levels of the lysosomal proteinase cathepsin S. Chloroquine, a lysosome inhibitor, restored the tyrosinase protein level downregulated by GIF-2202, although no effects of other inhibitors (against proteasome, autophagy, or exocytosis) were observed. In addition, GIF-2202 segregated the immunofluorescence signals of tyrosinase from those of TYRP1. Chloroquine treatment resulted in co-localization of tyrosinase and cathepsin S signals near the perinuclear region, suggesting that 4-OST and GIF-2202 may alter the destination of the tyrosinase vesicle from the melanosome to the lysosome. 4-OST and GIF-2202 can be new tools for studying the tyrosinase-specific vesicle transport system.
Keywords: chemical biology; melanocytes; melanogenesis; tyrosinase; vesicle transport.
Publication
Journal: Scientific Reports
November/13/2018
Abstract
In this study, we present an advanced nanofabrication approach, so-called 'heterogeneous pulse anodization' (HPA), in which galvanostatic stepwise and apodized sinusoidal pulse anodizations are combined in a single process. This novel anodization method enables the precise optical engineering of the characteristic photonic stopbands (PSBs) of nanoporous anodic alumina photonic crystals (NAA-PCs). The resulting structures are hybrid PCs (Hy-NAA-PCs) composed of distributed Bragg reflectors (DBRs) and apodized gradient-index filters (APO-GIFs) embedded within the same PC structure. The modification of various anodization parameters such as anodization period, relative and total anodization time, structural arrangement of PCs within Hy-NAA-PCs, and pore widening time allows the fine-tuning of the PSBs' features (i.e. number, position and bandwidth of central wavelength) across the spectral regions. The effects of these fabrication parameters are systematically assessed, revealing that the positions of the characteristic transmission bands of Hy-NAA-PCs are highly controllable. Our study provides a comprehensive rationale towards the development of unique Hy-NAA-PCs with controllable optical properties, which could open new opportunities for a plethora of applications.
Publication
Journal: IEEE transactions on image processing : a publication of the IEEE Signal Processing Society
July/22/2019
Abstract
Due to its local property, guided image filter (GIF) generally suffers from halo artifacts near edges. To make up for the deficiency, a weighted guided image filter (WGIF) was proposed recently by incorporating an edge-aware weighting into the filtering process. It takes the advantages of local and global operations, and achieves better performance in edge-preserving. However, edge direction, a vital property of the guidance image, is not considered fully in these guided filters. In order to overcome the drawback, we propose a novel version of GIF, which can leverage the edge direction more sufficiently. In particular, we utilize the steering kernel to adaptively learn the direction and incorporate the learning results into the filtering process to improve the filter's behavior. Theoretical analysis shows that the proposed method can get more powerful performance with preserving edges and reducing halo artifacts effectively. Similar conclusions are also reached through the thorough experiments including edge-aware smoothing, detail enhancement, denoising and dehazing.
Publication
Journal: Molecular BioSystems
July/23/2017
Abstract
Development of an interface tool between the Biochemical, Genetic and Genomic (BiGG) and KEGG databases is necessary for simultaneous access to the features of both databases. For this purpose, we present the BiKEGG toolbox, an open source COBRA toolbox extension providing a set of functions to infer the reaction correspondences between the KEGG reaction identifiers and those in the BiGG knowledgebase using a combination of manual verification and computational methods. Inferred reaction correspondences using this approach are supported by evidence from the literature, which provides a higher number of reconciled reactions between these two databases compared to the MetaNetX and MetRxn databases. This set of equivalent reactions is then used to automatically superimpose the predicted fluxes using COBRA methods on classical KEGG pathway maps or to create a customized metabolic map based on the KEGG global metabolic pathway, and to find the corresponding reactions in BiGG based on the genome annotation of an organism in the KEGG database. Customized metabolic maps can be created for a set of pathways of interest, for the whole KEGG global map or exclusively for all pathways for which there exists at least one flux carrying reaction. This flexibility in visualization enables BiKEGG to indicate reaction directionality as well as to visualize the reaction fluxes for different static or dynamic conditions in an animated manner. BiKEGG allows the user to export (1) the output visualized metabolic maps to various standard image formats or save them as a video or animated GIF file, and (2) the equivalent reactions for an organism as an Excel spreadsheet.
Publication
Journal: Horticulture Research
April/30/2021
Abstract
The growth of leaves and biosynthesis of characteristic secondary metabolites are critically important for tea production and quality control. However, little is known about the coordinated regulation of leaf development and catechin biosynthesis in tea plants. Here, we reported that TCP TFs are involved in both catechin biosynthesis and leaf development. An integrated analysis of catechin profiling and CsTCP expression in different tissues of plants under various environmental conditions at different developmental stages indicated significant correlations between the transcript levels of CIN-type TCPs and catechin production. CIN-type CsTCP3 and CsTCP4 and PCF-type CsTCP14 interacted with the MYB-bHLH-WD40 repeat (MBW) complex by forming a CsTCP3-CsTT8 heterodimer and modulating the transactivation activity of the promoters of anthocyanin synthase (CsANS1) and anthocyanidin reductase (CsANR1). Four types of microRNA/target modules, miR319b/CsTCP3-4, miR164b/CsCUC, miR396/CsGRF-GIF, and miR165b/HD-ZIPIII ones, were also identified and characterized for their functions in the regulation of the development of tea plant shoot tips and leaf shape. The results of these modules were reflected by their different expression patterns in developing buds and leaves that had distinctly different morphologies in three different tea plant varieties. Their roles in the regulation of catechin biosynthesis were also further verified by manipulation of microRNA319b (miR319b), which targets the transcripts of CsTCP3 and CsTCP4. Thus, CsTCPs represent at least one of these important groups of TFs that can integrate tea plant leaf development together with secondary metabolite biosynthesis. Our study provides new insight into shoot tip development and catechin production in tea plants and lays a foundation for further mechanistic understanding of the regulation of tea plant leaf development and secondary metabolism.
Publication
Journal: Nanoscale
June/7/2017
Abstract
We present the first realisation of linear variable bandpass filters in nanoporous anodic alumina (NAA-LVBPFs) photonic crystal structures. NAA gradient-index filters (NAA-GIFs) are produced by sinusoidal pulse anodisation and used as photonic crystal platforms to generate NAA-LVBPFs. The anodisation period of NAA-GIFs is modified from 650 to 850 s to systematically tune the characteristic photonic stopband of these photonic crystals across the UV-visible-NIR spectrum. Then, the nanoporous structure of NAA-GIFs is gradually widened along the surface under controlled conditions by wet chemical etching using a dip coating approach aiming to create NAA-LVBPFs with finely engineered optical properties. We demonstrate that the characteristic photonic stopband and the iridescent interferometric colour displayed by these photonic crystals can be tuned with precision across the surface of NAA-LVBPFs by adjusting the fabrication and etching conditions. Here, we envisage for the first time the combination of the anodisation period and etching conditions as a cost-competitive, facile, and versatile nanofabrication approach that enables the generation of a broad range of unique LVBPFs covering the spectral regions. These photonic crystal structures open new opportunities for multiple applications, including adaptive optics, hyperspectral imaging, fluorescence diagnostics, spectroscopy, and sensing.
load more...