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result(s) for
"Kwon, Edwin"
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The TGR5 receptor mediates bile acid–induced itch and analgesia
by
Schoonjans, Kristina
,
Nassini, Romina
,
Materazzi, Serena
in
Acids
,
Action Potentials
,
Animals
2013
Patients with cholestatic disease exhibit pruritus and analgesia, but the mechanisms underlying these symptoms are unknown. We report that bile acids, which are elevated in the circulation and tissues during cholestasis, cause itch and analgesia by activating the GPCR TGR5. TGR5 was detected in peptidergic neurons of mouse dorsal root ganglia and spinal cord that transmit itch and pain, and in dermal macrophages that contain opioids. Bile acids and a TGR5-selective agonist induced hyperexcitability of dorsal root ganglia neurons and stimulated the release of the itch and analgesia transmitters gastrin-releasing peptide and leucine-enkephalin. Intradermal injection of bile acids and a TGR5-selective agonist stimulated scratching behavior by gastrin-releasing peptide- and opioid-dependent mechanisms in mice. Scratching was attenuated in Tgr5-KO mice but exacerbated in Tgr5-Tg mice (overexpressing mouse TGR5), which exhibited spontaneous pruritus. Intraplantar and intrathecal injection of bile acids caused analgesia to mechanical stimulation of the paw by an opioid-dependent mechanism. Both peripheral and central mechanisms of analgesia were absent from Tgr5-KO mice. Thus, bile acids activate TGR5 on sensory nerves, stimulating the release of neuropeptides in the spinal cord that transmit itch and analgesia. These mechanisms could contribute to pruritus and painless jaundice that occur during cholestatic liver diseases.
Journal Article
Amyotrophic Lateral Sclerosis-Like Conditions in Possible Association with Cholesterol-Lowering Drugs
by
Golomb, Beatrice A.
,
Evans, Marcella A.
,
Kwon, Edwin K.
in
Amyotrophic lateral sclerosis
,
Biological and medical sciences
,
Clinical trial. Drug monitoring
2009
Background:
While cases of amyotrophic lateral sclerosis (ALS) or ALS-like conditions have arisen in apparent association with HMG-CoA reductase inhibitors (‘statins’) and/or other lipid-lowering drugs (collectively termed ‘statins’ in this paper for brevity), additional information is needed to understand whether the connection may be causal. The University of California, San Diego (UCSD) Statin Effects Study is a patient-targeted adverse event surveillance project focused on lipid-lowering agents, whose aim is to capitalize on patient reporting to further define characteristics and natural history of statin adverse effects (AEs), and to ascertain whether a patient-targeted surveillance system might lead to presumptive identification of previously unrecognized AEs. ALS was a candidate ‘new’ AE identified through this process. The aim of the analysis presented here was to examine characteristics and natural history of reported statin-associated ALS-like conditions with attention to factors that may bear on the issue of causality.
Methods:
For the present analysis, we focused on cases of statin-associated ALS that were reported to our study group prior to publication of a possible statin-ALS association. Of 35 identified subjects who had contacted the UCSD Statin Effects Study group to report ALS or an ALS-like condition, 18 could not be reached (e.g. contact information was no longer valid). Six were unable to participate (e.g. due to progression of their disease). Of the 11 who could be contacted and were able to participate, one declined to give informed consent. The remaining ten, with either a formal or probable diagnosis of ALS in the context of progressive muscle wasting/weakness arising in association with lipid-lowering drug therapy, completed a mail or phone survey eliciting information about ALS symptom onset and change in association with drug use/modification and development of statin-associated AEs. We reviewed findings in the context of literature on statin antioxidant/pro-oxidant balance, as well as ALS mechanisms involving oxidative stress and mitochondrial dysfunction.
Results:
All ten subjects reported amelioration of symptoms with drug discontinuation and/or onset or exacerbation of symptoms with drug change, rechallenge or dose increase. Three subjects initiated coenzyme Q10 supplementation; all reported initial benefit. All subjects reportedly developed statin AEs (not indicative of ALS) prior to ALS symptom onset, strongly disproportionate to expectation (p< 0.001). Since this reflects induction of pro-oxidant effects from statins, these findings lend weight to a literature-supported mechanism by which induction by statins of oxidative stress with amplification of mitochondrial dysfunction, arising in a vulnerable subgroup, may propel mechanisms underlying both AEs and, more rarely, ALS.
Conclusion:
A theoretical foundation and preliminary clinical observations suggest that statins (and other lipid-lowering drugs) may rarely be associated with ALS in vulnerable individuals in whom pro-oxidant effects of statins predominate. Our observations have explanatory relevance extending to ALS causes that are not statin associated and to statin-associated neurodegenerative conditions that are not ALS. They suggest means for identification of a possible vulnerable subgroup. Indeed whether statins may, in contrast, confer ALS protection when antioxidant effects predominate merits examination.
Journal Article
Hepatic surgery at a VA tertiary medical center: lessons learned
by
Kang, Sang-Mo
,
Alemi, Farzad
,
Kwon, Edwin
in
Academic Medical Centers - statistics & numerical data
,
Adult
,
Aged
2010
The development of a hepatic surgery center within a US Department of Veterans Affairs hospital is dependent on proper training and institutional support, which can translate into low operative morbidity and mortality rates.
Patients who underwent hepatic procedures between 2003 and 2009 were retrospectively reviewed. A subset analysis of laparoscopic liver resections for patients with hepatocellular cancer (HCC) was performed. One hundred twenty-six patients underwent 130 hepatic procedures, 65% of which were hepatic resections. Ninety-seven percent of cases were for malignant disease, including HCC (70%).
The morbidity and mortality rates were 15.5% and 2.4%, respectively. For patients with HCC there was no difference in operative outcomes or overall survival when procedures were performed laparoscopically.
A Veterans Affairs (VA) hospital specializing in hepatic surgery can achieve low complication rates comparable with those of high-volume centers. The numbers of patient referrals and hepatic resections and the proportion of laparoscopic operations increased after the creation of a dedicated hepatic surgery center within a single VA hospital.
Journal Article
Modulation of {Delta}F508 Cystic Fibrosis Transmembrane Regulator Trafficking and Function with 4-Phenylbutyrate and Flavonoids
2004
Over 70% of patients with cystic fibrosis have the DeltaF508 mutation. This protein is a partially functional chloride (Cl-) channel that is prematurely degraded in the endoplasmic reticulum. Specific members of the flavonoid class of compounds have been shown to increase Cl- conductance of wild-type and DeltaF508 cystic fibrosis transmembrane regulator (CFTR). Although flavonoid effects on CFTR processing are unknown, evidence of effects on heat shock proteins, specifically those that have been shown to interact with CFTR, led us to believe that there would be an effect on CFTR processing through modulation of CFTR-chaperone interactions. We sought to determine (i) the effect of apigenin, genistein, kaempferol, and quercetin on CFTR processing in IB3-1 cells (F508/W1282X) and (ii) whether sequential treatment with 4-phenylbutyrate (4-PBA) to increase CFTR processing and flavonoid to directly stimulate CFTR would increase Cl- conductance. Our results show no significant effect on CFTR processing as measured by immunoblotting with 1 microM or 5 microM of apigenin, genistein, kaempferol, or quercetin. However, despite no effect on CFTR processing as determined by immunoblot, immunofluorescence demonstrated a favorable change in the intracellular distribution of CFTR with 24 h treatments of apigenin, kaempferol, and genistein. Furthermore, we observed an increase in Cl- conductance as measured by Cl- efflux in cells that were treated for 24 h with 4-PBA and then assayed with forskolin and 1 microM or 5 microM genistein, and also with cells treated for 24 h with either 4-PBA, 5 microM apigenin, or 1 microM quercetin. Thus, a combination of chronic treatment with 4-PBA or select flavonoids, followed by acute flavonoid exposure, may be beneficial in cystic fibrosis.
Journal Article
Modulation of deltaF508 cystic fibrosis transmembrane regulator trafficking and function with 4-phenylbutyrate and flavonoids
by
Floyd, Alexandra D
,
Kwon, Edwin
,
McKenzie, Karen
in
Chlorides - metabolism
,
Cystic Fibrosis - genetics
,
Cystic Fibrosis Transmembrane Conductance Regulator - drug effects
2004
Over 70% of patients with cystic fibrosis have the DeltaF508 mutation. This protein is a partially functional chloride (Cl-) channel that is prematurely degraded in the endoplasmic reticulum. Specific members of the flavonoid class of compounds have been shown to increase Cl- conductance of wild-type and DeltaF508 cystic fibrosis transmembrane regulator (CFTR). Although flavonoid effects on CFTR processing are unknown, evidence of effects on heat shock proteins, specifically those that have been shown to interact with CFTR, led us to believe that there would be an effect on CFTR processing through modulation of CFTR-chaperone interactions. We sought to determine (i) the effect of apigenin, genistein, kaempferol, and quercetin on CFTR processing in IB3-1 cells (F508/W1282X) and (ii) whether sequential treatment with 4-phenylbutyrate (4-PBA) to increase CFTR processing and flavonoid to directly stimulate CFTR would increase Cl- conductance. Our results show no significant effect on CFTR processing as measured by immunoblotting with 1 microM or 5 microM of apigenin, genistein, kaempferol, or quercetin. However, despite no effect on CFTR processing as determined by immunoblot, immunofluorescence demonstrated a favorable change in the intracellular distribution of CFTR with 24 h treatments of apigenin, kaempferol, and genistein. Furthermore, we observed an increase in Cl- conductance as measured by Cl- efflux in cells that were treated for 24 h with 4-PBA and then assayed with forskolin and 1 microM or 5 microM genistein, and also with cells treated for 24 h with either 4-PBA, 5 microM apigenin, or 1 microM quercetin. Thus, a combination of chronic treatment with 4-PBA or select flavonoids, followed by acute flavonoid exposure, may be beneficial in cystic fibrosis.
Journal Article
Uncoupling the roles of synaptotagmin I during endo- and exocytosis of synaptic vesicles
2012
This study demonstrates a direct role for synaptotagmin I in the endocytosis of synaptic vesicles that is distinct from its role in exocytosis. In addition, the authors find that either of the C2 domains of syt1 can act as a calcium sensor during endocytosis.
Synaptotagmin I (syt1) is required for normal rates of synaptic vesicle endo- and exocytosis. However, whether the kinetic defects observed during endocytosis in
Syt1
knockout neurons are secondary to defective exocytosis or whether syt1 directly regulates the rate of vesicle retrieval remains unknown. To address this question, we sought to dissociate these two activities. We uncoupled the function of syt1 in exo- and endocytosis in mouse neurons either by re-targeting the protein or via mutagenesis of its tandem C2 domains. The effect of these manipulations on exo- and endocytosis were analyzed using electrophysiology, in conjunction with optical imaging of the vesicle cycle. Our results indicate that syt1 is directly involved in endocytosis. Notably, either of the C2 domains of syt1, C2A or C2B, was able to function as a Ca
2+
sensor for endocytosis. Thus, syt1 functions as a dual Ca
2+
sensor for both endo- and exocytosis, potentially coupling these two components of the vesicle cycle.
Journal Article
Emotion recognition while applying cosmetic cream using deep learning from EEG data; cross-subject analysis
2022
We report a deep learning-based emotion recognition method using EEG data collected while applying cosmetic creams. Four creams with different textures were randomly applied, and they were divided into two classes, “like (positive)” and “dislike (negative)”, according to the preference score given by the subject. We extracted frequency features using well-known frequency bands, i.e., alpha, beta and low and high gamma bands, and then we created a matrix including frequency and spatial information of the EEG data. We developed seven CNN-based models: (1) inception-like CNN with four-band merged input, (2) stacked CNN with four-band merged input, (3) stacked CNN with four-band parallel input, and stacked CNN with single-band input of (4) alpha, (5) beta, (6) low gamma, and (7) high gamma. The models were evaluated by the Leave-One-Subject-Out Cross-Validation method. In like/dislike two-class classification, the average accuracies of all subjects were 73.2%, 75.4%, 73.9%, 68.8%, 68.0%, 70.7%, and 69.7%, respectively. We found that the classification performance is higher when using multi-band features than when using single-band feature. This is the first study to apply a CNN-based deep learning method based on EEG data to evaluate preference for cosmetic creams.
Journal Article
Exome-based investigation of the genetic basis of human pigmentary glaucoma
by
Ritch, Robert
,
Roos, Ben R.
,
Goar, Wes
in
Animal Genetics and Genomics
,
Animals
,
Biomedical and Life Sciences
2021
Background
Glaucoma is a leading cause of visual disability and blindness. Release of iris pigment within the eye, pigment dispersion syndrome (PDS), can lead to one type of glaucoma known as pigmentary glaucoma. PDS has a genetic component, however, the genes involved with this condition are largely unknown. We sought to discover genes that cause PDS by testing cohorts of patients and controls for mutations using a tiered analysis of exome data.
Results
Our primary analysis evaluated melanosome-related genes that cause dispersion of iris pigment in mice (
TYRP1
,
GPNMB
,
LYST
,
DCT
, and
MITF
). We identified rare mutations, but they were not statistically enriched in PDS patients. Our secondary analyses examined
PMEL
(previously linked with PDS),
MRAP
, and 19 other genes. Four
MRAP
mutations were identified in PDS cases but not in controls (
p
= 0.016). Immunohistochemical analysis of human donor eyes revealed abundant MRAP protein in the iris, the source of pigment in PDS. However, analysis of
MRAP
in additional cohorts (415 cases and 1645 controls) did not support an association with PDS. We also did not confirm a link between
PMEL
and PDS in our cohorts due to lack of reported mutations and similar frequency of the variants in PDS patients as in control subjects.
Conclusions
We did not detect a statistical enrichment of mutations in melanosome-related genes in human PDS patients and we found conflicting data about the likely pathogenicity of
MRAP
mutations. PDS may have a complex genetic basis that is not easily unraveled with exome analyses.
Journal Article
Association of body mass index and COPD exacerbation among patients with chronic bronchitis
2022
Background and objective
Chronic obstructive pulmonary disease (COPD) patients with a body mass index (BMI) < 25 kg/m
2
are prone to develop adverse event of pharmacological treatment for frequent exacerbation. As chronic bronchitis (CB) is one of the strong risk factors of exacerbation, we investigated the associations between BMI and COPD exacerbations in patients with CB.
Methods
Patients with COPD were included from the Korean COPD Subgroup Study (KOCOSS), a multicenter observational cohort study. CB was defined using the St. George’s Respiratory Questionnaire and the participants were categorized according to BMI cut-off of 25 kg/m
2
. Exacerbations during a 1-year follow-up were compared among four groups: non-CB with BMI ≥ 25 kg/m
2
, non-CB with BMI < 25 kg/m
2
, CB with BMI ≥ 25 kg/m
2
, and CB with BMI < 25 kg/m
2
.
Results
Among the 1264 patients with COPD, 451 (35.7%) had CB and 353 (27.9%) had both CB and BMI < 25 kg/m
2
. The COPD exacerbation risk increased across the non-CB with BMI < 25 kg/m
2
, CB with BMI ≥ 25 kg/m
2
, and CB with BMI < 25 kg/m
2
groups (adjusted incidence rate ratio [95% confidence interval] 1.21 [0.89–1.62], 1.20 [0.77–1.88], and 1.41 [1.02–1.91], respectively, compared to the non-CB with BMI ≥ 25 kg/m
2
group).
Conclusions
COPD patients having both CB and a BMI < 25 kg/m
2
are at higher risk of exacerbations. Considering that a BMI < 25 kg/m
2
often limits treatment options preventing exacerbations, modified guidelines might be needed for non-obese CB patients in Asia.
Journal Article