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Increased alcohol consumption during the coronavirus disease 2019 pandemic is projected to impact alcohol-related liver disease (ALD) morbidity and mortality. Inter-hospital escalation-of-care referral requests to our tertiary-care hepatology unit were analyzed from January 2020 through December 2022. Most requests to our center were for ALD with an increase in requests from intermediate care units, suggestive of higher acuity illness.
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COVID-19 , Hepatopatías Alcohólicas , Humanos , Hepatopatías Alcohólicas/epidemiología , Hepatopatías Alcohólicas/terapia , Consumo de Bebidas Alcohólicas/epidemiología , Pandemias , COVID-19/epidemiología , Derivación y Consulta , HospitalesRESUMEN
Background: Sarcoidosis is a multisystem granulomatous disease with a wide variety of presentations and clinical courses. Cutaneous manifestations and comorbidities associated with sarcoid prognosis remain understudied. Methods: An EPIC query was run for patients age 18+ at the Johns Hopkins Hospital with a diagnosis of sarcoidosis of the skin according to the ICD-10-CM code D86.3. Data were obtained from a population-based sample of 240 patients from 2015 to 2020. Results: A total of 240 patients were included in the cohort study. The mean (SD) age was 43.76 (11.72) years, and 30% of participants were male; 76.25% of patients identified as black, 19.58% as white, and 4.17% as other. The average age of onset in remissive patients was significantly higher than progressive (47 ± 12 vs. 40 ± 10, p = 0.0005); 49% of black patients experienced progressive sarcoid compared to 32.6% of white patients (p = 0.028). Progressive disease was associated with the presence of lupus pernio (aOR = 3.29, 95% CI, 1.60-6.77) and at least one autoimmune comorbidity (aOR 6.831, 95% CI 1.819-11.843). Conclusions: When controlling for patient demographics, lupus pernio and the presence of at least one autoimmune condition were associated with progressive cutaneous sarcoidosis.
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Our objective was to describe the use of medications associated with weight change among US adults with overweight/obesity, including anti-obesity medications (AOMs), weight-loss-promoting and weight-gain-promoting medications. We performed a cross-sectional analysis of data from the nationwide All of Us Research Programme. We included adults with measured body mass index (BMI) ≥ 27 kg/m2 enrolled between 2018 and 2022 across the United States. We used linked electronic health record data to determine medication use ±12 months of BMI measure. Our 132 057 participants had mean age 54 years and mean BMI 34 kg/m2 ; 60% of participants were women, 62% White, and 32% Black. Only 1% used any AOM, and 14% used at least one weight-loss-promoting medication. We found that 36% used at least one weight-gain-promoting medication, and approximately 20% used multiple weight-gain-promoting medications. While AOMs are underutilized by participants with overweight/obesity, weight-gain-promoting medication use is common. Our results raise concern about potential iatrogenic weight gain from medications. Future research is needed to estimate the long-term effect of weight-gain-promoting medications on weight status and determine whether weight-loss benefits occur with their discontinuation. Clinician education on AOMs and weight-loss-promoting medications may be needed to increase their use.
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Fármacos Antiobesidad , Salud Poblacional , Adulto , Humanos , Femenino , Estados Unidos , Persona de Mediana Edad , Masculino , Sobrepeso/tratamiento farmacológico , Estudios Transversales , Obesidad/tratamiento farmacológico , Índice de Masa Corporal , Aumento de Peso , Fármacos Antiobesidad/efectos adversosRESUMEN
BACKGROUND: Controlled radial expansion (CRE) balloon dilators are traditionally used to dilate esophageal strictures during an esophagogastroduodenoscopy (EGD). EndoFLIP is a diagnostic tool used during an EGD to measure important parameters of the gastrointestinal lumen, capable of assessing treatment before and after dilation. EsoFLIP is a related device that combines a balloon dilator with high-resolution impedance planimetry to provide some of the luminal parameters in real time during dilation. We sought to compare procedure time, fluoroscopy time, and safety profile of esophageal dilation using either CRE balloon dilation combined with EndoFLIP (E + CRE) versus EsoFLIP alone. METHODS: A single-center retrospective review was performed to identify patients ≤ 21 years of age who underwent an EGD with biopsy and esophageal stricture dilation using E + CRE or EsoFLIP between October 2017 and May 2022. RESULTS: Twenty-nine EGDs with esophageal stricture dilation were performed in 23 patients (19 E + CRE and 10 EsoFLIP). The two groups did not differ in age, gender, race, chief complaint, type of esophageal stricture, or history of prior gastrointestinal procedures (all p > 0.05). The most common medical history in the E + CRE and EsoFLIP groups were eosinophilic esophagitis and epidermolysis bullosa, respectively. Median procedures times were shorter in the EsoFLIP cohort compared to E + CRE balloon dilation (40.5 min [IQR 23-57 min] for the EsoFLIP group; 64 min [IQR 51-77 min] for the E + CRE group; p < 0.01). Median fluoroscopy times were also shorter for patients who underwent EsoFLIP (0.16 min [IQR 0-0.30 min] for EsoFLIP dilation; 0.30 min [IQR 0.23-0.55] for the E + CRE group; p = 0.003). There were no complications or unplanned hospitalizations in either group. CONCLUSION: EsoFLIP dilation of esophageal strictures was faster and required less fluoroscopy than CRE balloon dilation combined with EndoFLIP in children, while being equally as safe. Prospective studies are needed to further compare the two modalities.
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Estenosis Esofágica , Humanos , Niño , Estenosis Esofágica/etiología , Estenosis Esofágica/terapia , Constricción Patológica , Dilatación/métodos , Resultado del Tratamiento , Estudios RetrospectivosRESUMEN
Liver transplantation (LT) candidates frequently have multiple cardiovascular risk factors, and cardiovascular disease is a major cause of morbidity and mortality after LT. Coronary artery calcium (CAC) scores are a noninvasive assessment of coronary artery disease using computed tomography. This study examines CAC scores and cardiac risk factors and their association with outcomes after LT. Methods: Patients who underwent LT between January 2010 and June 2019 with a pretransplant CAC score were included in this study. Patients were divided by CAC score into 4 groups (CAC score 0, CAC score 1-100, CAC score 101-400, CAC score >400). Major adverse cardiovascular events (MACEs) were defined as myocardial infarction, stroke, revascularization, heart failure, atrial fibrillation, and cardiovascular death. Associations between CAC score and MACE or all-cause mortality within the 5-y post-LT follow-up period were analyzed using Cox regression. Statistical significance was defined as P < 0.05. Results: During the study period, 773 adult patients underwent their first LT, and 227 patients met our study criteria. The median follow-up time was 3.4 (interquartile range 1.9, 5.3) y. After 5 y, death occurred in 47 patients (20.7%) and MACE in 47 patients (20.7%). In multivariable analysis, there was no difference in death between CAC score groups. There was significantly higher risk of MACE in the CAC score >400 group, with a hazard ratio 2.58 (95% confidence interval 1.05, 6.29). Conclusions: CAC score was not associated with all-cause mortality. Patients with CAC score >400 had an increase in MACEs within the 5-y follow-up period compared with patients with a CAC score = 0. Further research with larger cohorts is needed to examine cardiac risk stratification in this vulnerable patient population.
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BACKGROUND: Immediate postoperative extubation (IPE) can reduce perioperative complications and length of stay (LOS), however it is performed variably after liver transplant across institutions and has historically excluded high-risk recipients from consideration. In late 2012, we planned and implemented a single academic institution structured quality improvement (QI) initiative to standardize perioperative care of liver transplant recipients without exceptions. We hypothesized that such an approach would lead to a sustained increase in IPE after primary (PAC) and delayed abdominal closure (DAC). METHODS: We retrospectively studied 591 patients from 2013 to 2018 who underwent liver transplant after initiative implementation. We evaluated trends in incidence of IPE versus delayed extubation (DE), and reintubation, LOS, and mortality. RESULTS: Overall, 476/591 (80.5%) recipients underwent PAC (278 IPE, 198 DE) and 115/591 (19.5%) experienced DAC (39 IPE, 76 DE). When comparing data from 2013 to data from 2018, the incidence of IPE increased from 9/67 (13.4%) to 78/90 (86.7%) after PAC and from 1/12 (8.3%) to 16/23 (69.6%) after DAC. For the same years, the incidence of IPE after PAC for recipients with MELD scores ≥30 increased from 0/19 (0%) to 12/17 (70.6%), for recipients who underwent simultaneous liver-kidney transplant increased from 1/8 (12.5%) to 4/5 (80.0%), and for recipients who received massive transfusion (>10 units of packed red blood cells) increased from 0/17 (0%) to 10/13 (76.9%). Reintubation for respiratory considerations <48 h after IPE occurred in 3/278 (1.1%) after PAC and 1/39 (2.6%) after DAC. IPE was associated with decreased intensive care unit (HR of discharge: 1.92; 95% CI: 1.58, 2.33; P < 0.001) and hospital LOS (HR of discharge: 1.45; 95% CI: 1.20, 1.76; P < 0.001) but demonstrated no association with mortality. CONCLUSION: A structured QI initiative led to sustained high rates of IPE and reduced LOS in all liver transplant recipients, including those classified as high risk.
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Trasplante de Hígado , Humanos , Trasplante de Hígado/efectos adversos , Estudios Retrospectivos , Extubación Traqueal/efectos adversos , Hígado , Periodo Posoperatorio , Tiempo de InternaciónRESUMEN
BACKGROUND: Endoluminal functional lumen imaging probe (EndoFLIP) is a minimally invasive, novel device that uses high-resolution impedance planimetry to measure important parameters of the gastrointestinal lumen that aid in the diagnosis of esophageal disorders. EndoFLiP is approved by the US Food and Drug Administration (FDA) for children 5âyears and older. We sought to compare its safety and luminal characteristics between children under 5âyears of age with children 5âyears and older. METHODS: A single-center retrospective review was performed to identify all patients <â21âyears of age who underwent esophagogastroduodenoscopy (EGD) with EndoFLIP between October 2017 and November 2020. Results: Sixty-seven EGDs with EndoFLIP were performed in 56 patients, including 14 that were done in children <â5âyears and 53 in children ≥5years. The median age in the <â5-year group was 1.7years (interquartile range [IQR], 0.9-4.4) and the youngest patient was 1âmonth old. The median age in ≥5-year group was 14.3âyears (IQR, 8.2-16.2). Median procedure times were similar (32âminutes [IQR, 25-48] for the <â5-year group; 28 minutes [IQR, 20-33] for ≥5-year group; Pâ =â0.08). There were no adverse events or unplanned hospitalizations in either group. At 30âmL inflation, the pressure of the lower esophageal sphincter (LES) was statistically different between the 2 groups (Pâ=â0.02). CONCLUSION: EndoFLIP appears to be safe for use in our small cohort of children <â5âyears of age and may be an important tool in the management of esophageal disorders in this age group. There was no difference in procedure time between our 2 age groups and there were no procedure-related complications.
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Enfermedades del Esófago , Esfínter Esofágico Inferior , Adolescente , Niño , Preescolar , Estudios de Cohortes , Impedancia Eléctrica , Esfínter Esofágico Inferior/cirugía , Humanos , Lactante , Estudios RetrospectivosRESUMEN
Alcohol sales and consumption have increased during the coronavirus disease 2019 pandemic, but their downstream effects on alcohol-related liver disease (ALD) are unclear. We analyzed inter-hospital escalation-of-care referrals to our tertiary care inpatient liver unit across 18 months through December 2020. There was a significant rise in severe ALD with recent unhealthy drinking in our regional community during the pandemic.
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COVID-19 , Hepatopatías , Consumo de Bebidas Alcohólicas/epidemiología , COVID-19/epidemiología , Hospitales , Humanos , Pandemias , Derivación y ConsultaRESUMEN
BACKGROUND AND AIMS: It is unclear whether the common practice of postoperative day (POD) 1 esophagram impacts clinical care or reliably identifies significant adverse events (AEs) related to peroral endoscopic myotomy (POEM). Therefore, we aimed to correlate the most clinically relevant esophagram findings with postoperative outcomes after POEM. METHODS: Patients were retrospectively reviewed and included if they underwent POEM at 1 of the 3 study institutions between 2014 and 2018. Patient outcomes were assessed in relation to relevant POD 1 esophagram findings such as esophageal dissection or leak. RESULTS: One hundred seventy post-POEM contrast esophagrams (139 fluoroscopy-based vs 31 CT-based) performed on POD 1 were included. Most esophagrams (n = 98) contained abnormal findings but only 5 showed esophageal leak or dissection. Confirmed postoperative AEs of leak or dissection occurred in 4 patients. In 2 patients, POD 1 esophagram appropriately identified the leak or dissection, but in the other 2 patients the initial esophagram was negative, and the AEs were not recognized before clinical deterioration. One patient had a false-positive leak and dissection noted on esophagram leading to an unremarkable endoscopy. CONCLUSIONS: Despite the low AE rate after POEM, follow-up esophagram on POD 1 frequently shows expected, unremarkable postprocedural findings and occasionally fails to diagnose serious AEs. This results in pitfalls in accuracy regarding agreement between esophagram versus clinical and endoscopic findings. Relying exclusively on esophagram for post-POEM clinical decision-making can lead to unnecessary additional testing or missed AEs.
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Acalasia del Esófago , Miotomía , Cirugía Endoscópica por Orificios Naturales , Acalasia del Esófago/cirugía , Esfínter Esofágico Inferior/cirugía , Humanos , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
Microscopic colitis (MC) is characterized by chronic watery diarrhea, endoscopically normal findings, and abnormal histology. While mostly encountered in adults, pediatric cases are rare and may show varying presentations. Our pathology data system was searched from 1984 to 2019 for patients ≤18 years of age with a lymphocytic colitis (LC) or collagenous colitis (CC) pattern of injury. Twenty-seven cases (23 LC and 4 CC) were retrieved. LC was more prevalent than CC (85% vs 15%, respectively) and affected slightly younger individuals (mean, 9.8 years versus 12.25 years). Immune dysregulation was documented in 11 (41%) patients. Most patients presented with watery diarrhea (n = 26, 96%) and either abdominal pain (n = 18, 67%), nausea/vomiting (n = 5, 19%), flatulence (n = 6, 22%), and/or weight loss (n = 1, 4%). A subset of patients (n = 10, 37%) demonstrated endoscopic abnormalities. Histologically, some patients with LC and CC displayed focal cryptitis or crypt abscess formation (n = 7, 26%) and focally increased crypt apoptosis (n = 9, 33%) in the absence of chronic injury. Clinical follow-up data were available for 23 (85%) patients with variable clinical responses recorded. Only 8 patients experienced complete symptom resolution. Twelve patients (11 LC and 1 CC) had subsequent biopsy material; of which, one developed histologic features of inflammatory bowel disease and another was found to have a CTLA-4 deficiency. Our study shows that pediatric patients with MC may have atypical clinical, histologic, and endoscopic findings and variable clinical responses. Underlying inflammatory and/or genetic conditions may be eventually unmasked, and genetic testing may be helpful in a small subset of patients.
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Colitis Colagenosa/patología , Colitis Linfocítica/patología , Colon/patología , Adolescente , Factores de Edad , Biopsia , Antígeno CTLA-4/genética , Niño , Preescolar , Colitis Colagenosa/complicaciones , Colitis Colagenosa/inmunología , Colitis Linfocítica/complicaciones , Colitis Linfocítica/genética , Colitis Linfocítica/inmunología , Colon/inmunología , Colonoscopía , Análisis Mutacional de ADN , Bases de Datos Factuales , Femenino , Predisposición Genética a la Enfermedad , Humanos , Masculino , Mutación , Pronóstico , Medición de Riesgo , Factores de Riesgo , Factores de TiempoRESUMEN
Background: Granuloma annulare (GA) is a cutaneous granulomatous disorder of unknown etiology. There are conflicting data on the association between GA and multiple systemic conditions. As a result, we aimed to clarify the reported associations between GA and systemic conditions. Methods: A retrospective, cross-sectional, case-control study was performed in which the medical records of biopsy-confirmed GA patients ≥18 years of age, who presented to the Johns Hopkins Hospital System between 1 January 2009 and 1 June 2019, were reviewed. GA patients were compared to controls matched for age, race, and sex. Results: After adjusting for confounders, GA patients (n = 82) had higher odds of concurrent type II diabetes (odds ratio (OR) = 5.27; 95% confidence interval (CI), 1.73-16.07; p < 0.01), non-migraine headache (OR = 8.70; 95% CI, 1.61-46.88; p = 0.01), and a positive smoking history (OR = 1.93; 95% CI, 1.10-3.38; p = 0.02) compared to controls (n = 164). Among GA patients, women were more likely to have ophthalmic conditions (p = 0.04), and men were more likely to have cardiovascular disease (p < 0.01) and type II diabetes (p = 0.05). No differences in systemic condition associations were observed among GA subtypes. Conclusions: Our results support the reported association between GA and type II diabetes. Furthermore, our findings indicate that GA may be associated with cigarette smoking and non-migraine headache disorders.
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Background and study aims Esophagogastric junction outflow obstruction (EGJOO) is a rare esophageal dysmotility disease that is characterized by elevated integrated relaxation pressuse (IRP) with evidence of preserved peristalsis. The role of peroral endoscopic myotomy (POEM) in management of EGJOO is currently unknown. Patients and methods This is a prospective trial conducted in a single US tertiary care center from June 2015 to June 2019.âSymptomatic patients, diagnosed with EGJOO on both HRM and endoluminal functional lumen imaging probe (EndoFLIP), who were eligible for POEM were recruited. Primary outcome was clinical success, defined as Eckardt score (ES) ≤â3, at 6 months post-POEM. Other outcomes included dysphagia score, quality of life as measured by 36-item Short Form health survey scales (SF-36), post-POEM HRM, EndoFLIP, and pH measurements, and adverse events. Results A total of 15 patients (51.8 yr. 9 F) with EGJOO underwent POEM. Pre-POEM mean IRP on HRM and Distensibility index (DI) on EndoFLIP were 24.3â±â2.2âmmHg and 1.1â±â0.6âmm 2 /mmHg, respectively. Clinical success was achieved in 93â% at 6 months post-POEM. There was significant decrease in IRP (-17.6âmmHg) post-POEM. There was significant improvement at 6 months in two of the SF-36 subscales. Ten patients underwent post-POEM pH testing, seven of whom had abnormal DeMeester score. Seven patients underwent EGD evaluation revealing esophagitis in five (2 Los Angeles grade A and 3 grade B). Conclusions POEM offers a high clinical success rate for patients with EGJOO confirmed by impedance planimetry.
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Excoriation disorder is a psychocutaneous disorder characterized by repetitive skin-picking and associated with significant morbidity. Currently, epidemiological data in patients with excoriation disorder are lacking so we sought to characterize common patient demographics and comorbidities. We conducted a retrospective case-control study comparing 250 patients with excoriation disorder with 250 age-, race- and sex-matched controls identified between 2007 and 2019 at a single tertiary care center. We found that the majority of excoriation disorder patients were female (76%), Caucasian (82%) and unmarried (62%), with a mean age of 49 years. Compared to the matched controls, patients with excoriation disorder had increased odds of several psychiatric illnesses, including obsessive compulsive disorder (odds ratio (OR) 28.48, 95% confidence interval (CI): 1.68, 481.75), substance use disorder (OR 24.33, 95% CI: 5.81, 101.77), post-traumatic stress disorder (OR 8.23, 95% CI: 2.24, 129.40), depression (OR 8.19, 95% CI: 4.86, 13.80), bipolar disorder (OR 7.55, 95% CI: 2.22, 25.65), attention-deficit/hyperactivity disorder (OR 5.63, 95% CI: 1.62, 19.57), and anxiety (OR 5.01, 95% CI: 2.92, 8.62). Only a minority (42%) of patients were given psychiatry referrals and of those referred, a majority (64%) did not follow-up with psychiatry. The outcomes were also generally unfavorable as only 21% of patients experienced a resolution or improvement in their symptoms. This highlights the need for a multidisciplinary approach to manage patients with excoriation disorder, involving both dermatologists and psychiatrists.
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Heterotopic pancreas is pancreatic tissue present outside of the normal location of the pancreas. In the presence of cystic degeneration, heterotopic pancreas is clinically significant because of the symptoms it causes and its physical resemblance to cancerous growth. A diagnosis of heterotopic pancreas is achieved with the aid of various endoscopic techniques for tissue removal. Submucosal tunneling endoscopic resection has proven successful for the resection of gastric subepithelial masses. We present a 53-year-old woman undergoing submucosal tunneling endoscopic resection for the resection of a subepithelial gastric cyst caused by heterotopic pancreas with cystic degeneration.
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BACKGROUND: Renal replacement therapies (RRT) other than in-centre haemodialyses are underutilised by African Americans with end-stage renal disease (ESRD) even though they are associated with reduced costs, morbidity and mortality as well as improved quality of life for patients. OBJECTIVES: To understand African American patients' knowledge of RRT options and how patient, provider and system-factors contribute to knowledge and preferences. Participants' interviews were conducted at the University of Chicago Medical Center with African American patients with chronic kidney disease (CKD). The final analysis included 28 interviews; 22 patients had CKD not yet on dialysis or having received a transplant, while 6 had reached ESRD and were receiving treatment for kidney failure. Approach Transcripts were uploaded into NVivo8 for coding. Thematic analysis was used for data interpretation. RESULTS: Four themes were identified: (1) limited knowledge of home modalities and deceased donor options, (2) CKD patients gave little thought to choosing RRT options, (3) CKD patients relied on doctors for treatment decisions, and (4) while patients reported knowledge of living kidney donation transplants (LKDT), it did not translate to receiving an LKDT. CONCLUSION: African Americans face significant knowledge and access barriers when deciding on their RRT treatment. Even patients with advanced CKD were still in the early stages of RRT selection. Understanding the knowledge gaps and barriers patients face will inform our subsequent intervention to educate and motivate patients to increase CKD self-care and improve communication between patients, their families and their providers about different RRT treatments.
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Negro o Afroamericano/psicología , Conocimientos, Actitudes y Práctica en Salud/etnología , Insuficiencia Renal Crónica/complicaciones , Terapia de Reemplazo Renal/métodos , Adolescente , Adulto , Negro o Afroamericano/etnología , Negro o Afroamericano/estadística & datos numéricos , Anciano , Femenino , Alfabetización en Salud/normas , Alfabetización en Salud/estadística & datos numéricos , Humanos , Entrevistas como Asunto/métodos , Masculino , Persona de Mediana Edad , Investigación Cualitativa , Insuficiencia Renal Crónica/psicología , Insuficiencia Renal Crónica/terapia , Terapia de Reemplazo Renal/instrumentación , Terapia de Reemplazo Renal/psicologíaRESUMEN
CONTEXT: African-Americans with chronic kidney disease (CKD) are more likely to progress to end-stage renal disease (ESRD). However, African-Americans are less likely to receive care to delay progression of their CKD and to prepare for ESRD treatment. OBJECTIVE: The objectives of the study are to understand knowledge among urban, African-American patients diagnosed with CKD and to discover ways they managed their illness and prepared for kidney disease progression. DESIGN: A qualitative study was conducted using structured interviews. Thematic analysis was used for data interpretation. All 23 participants identified as African-American and had CKD but had not yet reached ESRD requiring renal replacement therapy (RRT). Over half of the participants were women (57%), and the mean age was 53 years old. RESULTS: Three themes emerged from the data. African-Americans often did not know the severity of their CKD. They struggled to complete all of the diet, exercise, and medication tasks recommended to manage their health conditions, including CKD. Finally, participants, even those with stage 5 CKD, viewed progression to RRT in the next 12 months as unlikely. CONCLUSION: African-Americans face many barriers to CKD self-care and preparation for ESRD. Improving outcomes requires clinicians to help patients understand the severity of their CKD, to make informed choices about their care, all the while motivating patients to take actions to prevent CKD progression.
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Adaptación Psicológica , Actitud Frente a la Salud , Negro o Afroamericano/psicología , Insuficiencia Renal Crónica/psicología , Población Urbana/estadística & datos numéricos , Adolescente , Adulto , Negro o Afroamericano/estadística & datos numéricos , Anciano , Progresión de la Enfermedad , Femenino , Humanos , Entrevistas como Asunto , Masculino , Persona de Mediana Edad , Investigación Cualitativa , Adulto JovenRESUMEN
Dorsal root ganglion (DRG) neurons process pain signaling through specialized nociceptors located in their peripheral endings. It has long been established low voltage-activated (LVA) CaV3.2 calcium channels control neuronal excitability during sensory perception in these neurons. Silencing CaV3.2 activity with antisense RNA or genetic ablation results in anti-nociceptive, anti-hyperalgesic and anti-allodynic effects. CaV3.2 channels are regulated by many proteins (Weiss and Zamponi, 2017), including KLHL1, a neuronal actin-binding protein that stabilizes channel activity by recycling it back to the plasma membrane through the recycling endosome. We explored whether manipulation of KLHL1 levels and thereby function as a CaV3.2 modifier can modulate DRG excitability and mechanical pain transmission or sensitivity to pain. We first assessed the mechanical sensitivity threshold and DRG properties in the KLHL1 KO mouse model. KO DRG neurons exhibited smaller T-type current density compared to WT without significant changes in voltage dependence, as expected in the absence of its modulator. Western blot analysis confirmed CaV3.2 but not CaV3.1, CaV3.3, CaV2.1, or CaV2.2 protein levels were significantly decreased; and reduced neuron excitability and decreased pain sensitivity were also found in the KLHL1 KO model. Analogously, transient down-regulation of KLHL1 levels in WT mice with viral delivery of anti-KLHL1 shRNA also resulted in decreased pain sensitivity. These two experimental approaches confirm KLHL1 as a physiological modulator of excitability and pain sensitivity, providing a novel target to control peripheral pain.
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Kelch-like 1 (KLHL1) is a neuronal actin-binding protein that modulates voltage-gated CaV2.1 (P/Q-type) and CaV3.2 (α1H T-type) calcium channels; KLHL1 knockdown experiments (KD) cause down-regulation of both channel types and altered synaptic properties in cultured rat hippocampal neurons (Perissinotti et al., 2014). Here, we studied the effect of ablation of KLHL1 on calcium channel function and synaptic properties in cultured hippocampal neurons from KLHL1 knockout (KO) mice. Western blot data showed the P/Q-type channel α1A subunit was less abundant in KO hippocampus compared to wildtype (WT); and P/Q-type calcium currents were smaller in KO neurons than WT during early days in vitro, although this decrease was compensated for at late stages by increases in L-type calcium current. In contrast, T-type currents did not change in culture. However, biophysical properties and western blot analysis revealed a differential contribution of T-type channel isoforms in the KO, with CaV3.2 α1H subunit being down-regulated and CaV3.1 α1G up-regulated. Synapsin I levels were also reduced in the KO hippocampus and cultured neurons displayed a concomitant reduction in synapsin I puncta and decreased miniature excitatory postsynaptic current (mEPSC) frequency. In summary, genetic ablation of the calcium channel modulator resulted in compensatory mechanisms to maintain calcium current homeostasis in hippocampal KO neurons; however, synaptic alterations resulted in a reduction of excitatory synapse number, causing an imbalance of the excitatory-inhibitory synaptic input ratio favoring inhibition.