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1.
J Child Media ; 18(2): 159-177, 2024.
Article in English | MEDLINE | ID: mdl-38715946

ABSTRACT

Adolescents spend a substantial portion of their time using social media. Yet, there is a lack of understanding regarding how often parents and adolescents communicate about this social media use. To address this gap, we developed the Parent-Adolescent Communication about Adolescents' Social Media Use Scale (PACAS). In a first data wave, among 388 Dutch adolescents (13-15 years; 54% girls), exploratory and confirmatory factor analyses distinguished four scales: parental solicitation, adolescent disclosure, adolescent secrecy, and parental knowledge. All four scales had strong internal reliability and correlated in the expected directions. We re-established the validity and internal reliability and obtained test-retest reliability in a second wave, in which 330 adolescents were surveyed again. The findings show that parents and adolescents infrequently communicate about social media. Parental knowledge about adolescents' social media use strongly depends on the communication efforts of both parties. Altogether, the PACAS provides a valuable tool to explore the dynamics of parent-adolescent communication about social media.


Prior State of Knowledge: Adolescents use social media around the clock. This raises concerns among parents about what their adolescents do and experience on social media. Yet, our understanding of how parents and adolescents communicate about these issues is limited. Novel Contributions: This study developed the Parent-Adolescent Communication about Adolescents' Social Media Use Scale (PACAS), which consists of four scales: parental solicitation, adolescent disclosure, adolescent secrecy, and parental knowledge. The findings show that parents and adolescents infrequently communicate about social media. Practical Implications: The findings emphasize that parents should not only solicit information but also foster open communication so that adolescents can willingly disclose information about their social media use. Only then can parents keep informed about their adolescents' social media experiences.

2.
Nucleic Acids Res ; 52(D1): D138-D144, 2024 Jan 05.
Article in English | MEDLINE | ID: mdl-37933855

ABSTRACT

The Gene Expression Omnibus (GEO) is an international public repository that archives gene expression and epigenomics data sets generated by next-generation sequencing and microarray technologies. Data are typically submitted to GEO by researchers in compliance with widespread journal and funder mandates to make generated data publicly accessible. The resource handles raw data files, processed data files and descriptive metadata for over 200 000 studies and 6.5 million samples, all of which are indexed, searchable and downloadable. Additionally, GEO offers web-based tools that facilitate analysis and visualization of differential gene expression. This article presents the current status and recent advancements in GEO, including the generation of consistently computed gene expression count matrices for thousands of RNA-seq studies, and new interactive graphical plots in GEO2R that help users identify differentially expressed genes and assess data set quality. The GEO repository is built and maintained by the National Center for Biotechnology Information (NCBI), a division of the National Library of Medicine (NLM), and is publicly accessible at https://www.ncbi.nlm.nih.gov/geo/.


Subject(s)
Epigenomics , Gene Expression Profiling , Gene Expression , Databases, Genetic , Oligonucleotide Array Sequence Analysis
4.
MMWR Morb Mortal Wkly Rep ; 72(38): 1032-1040, 2023 Sep 22.
Article in English | MEDLINE | ID: mdl-37733637

ABSTRACT

Mental and behavioral health conditions among school-aged children, including substance use disorders and overall emotional well-being, are a public health concern in the United States. Timely data on seasonal patterns in child and adolescent conditions can guide optimal timing of prevention and intervention strategies. CDC examined emergency department (ED) visit data from the National Syndromic Surveillance Program for 25 distinct conditions during January 2018-June 2023 among U.S. children and adolescents aged 5-17 years, stratified by age group. Each year, during 2018-2023, among persons aged 10-14 and 15-17 years, the number and proportion of weekly ED visits for eight conditions increased in the fall school semester and remained elevated throughout the spring semester; ED visits were up to twice as high during school semesters compared with the summer period. Among children aged 5-9 years, the number and proportion of visits increased for five mental and behavioral health conditions. Seasonal increases in ED visits for some conditions among school-aged children warrant enhanced awareness about mental distress symptoms and the challenges and stressors in the school environment. Systemic changes that prioritize protective factors (e.g., physical activity; nutrition; sleep; social, community, or faith-based support; and inclusive school and community environments) and incorporate preparedness for increases in conditions during back-to-school planning might improve child and adolescent mental health.


Subject(s)
Emergency Service, Hospital , Mental Disorders , Mental Health , Adolescent , Child , Humans , Mental Disorders/epidemiology , Mental Disorders/therapy , Seasons , United States/epidemiology
5.
Osteoporos Sarcopenia ; 9(1): 14-21, 2023 Mar.
Article in English | MEDLINE | ID: mdl-37082356

ABSTRACT

Objectives: To define what portion of older community men with what severity of radiographic osteoporotic-like vertebral fracture (OLVF) correspond to what low T-score status. Methods: There were 755 community Chinese men (age: 76.4 ± 6.7 years) with thoracic and lumbar spine radiographs, and hip and lumbar spine bone mineral density measures. For each vertebra in a subject, a score of 0, -0.5, -1, -1.5, -2, -2.5, and -3 was assigned for no OLVF or OLVF of <20%, ≥ 20-25%, ≥ 2 5%-1/3, ≥ 1/3-40%, ≥ 40%-2/3, and ≥ 2/3 vertebral height loss, respectively. OLVFss was defined as the summed score of vertebrae T4 to L5. OLVFss and T-scores were ranked from the smallest to the largest values. Results: OLVFss of -2, -2.5, -3, corresponded to a mean femoral neck T-score of -2.297 (range: -2.355∼-2.247), -2.494 (range: -2.637∼ -2.363), and -2.773 (range: -2.898∼-2.643), a mean hip T-score of-2.311 (range: -2.420∼-2.234), -2.572 (range: -2.708∼-2.432), -2.911 (range: -3.134∼-2.708), a mean lumbar spine T-score of -2.495 (range: -2.656∼-2.403), -2.931 (range: -3.255∼-2.664), and -3.369 (range: -3.525∼-3.258). The Pearson correlation value of OLVFss and T-score of femoral neck, hip and lumbar spine was r = 0.21, 0.26, and 0.22 (all P < 0.0001). Conclusions: A single severe grade radiological OLVF (≥ 40% height loss) or OLVFss ≤ -2.5 suggest the subject is osteoporotic, and a single collapse grade (≥ 2/3 height loss) OLVF or OLVFss ≤ -3 meets osteoporosis diagnosis criterion. The results highlight the difficulty of diagnosing osteoporotic vertebral fractures among Chinese older men.

6.
Article in English | WPRIM (Western Pacific) | ID: wpr-1002657

ABSTRACT

Objectives@#To define what portion of older community men with what severity of radiographic osteoporotic-like vertebral fracture (OLVF) correspond to what low T-score status. @*Methods@#There were 755 community Chinese men (age: 76.4 ± 6.7 years) with thoracic and lumbar spine radiographs, and hip and lumbar spine bone mineral density measures. For each vertebra in a subject, a score of 0, -0.5, −1, −1.5, −2, −2.5, and −3 was assigned for no OLVF or OLVF of <20%, ≥ 20–25%, ≥ 2 5%–1/3, ≥ 1/3–40%, ≥ 40%–2/3, and ≥ 2/3 vertebral height loss, respectively. OLVFss was defined as the summed score of vertebrae T4 to L5. OLVFss and T-scores were ranked from the smallest to the largest values. @*Results@#OLVFss of −2, −2.5, −3, corresponded to a mean femoral neck T-score of −2.297 (range: -2.355∼-2.247), −2.494 (range: -2.637∼ −2.363), and −2.773 (range: -2.898∼-2.643), a mean hip T-score of-2.311 (range: -2.420∼-2.234), −2.572 (range: -2.708∼-2.432), −2.911 (range: -3.134∼-2.708), a mean lumbar spine T-score of −2.495 (range: -2.656∼-2.403), −2.931 (range: -3.255∼-2.664), and −3.369 (range: -3.525∼-3.258). The Pearson correlation value of OLVFss and T-score of femoral neck, hip and lumbar spine was r = 0.21, 0.26, and 0.22 (all P < 0.0001). @*Conclusions@#A single severe grade radiological OLVF (≥ 40% height loss) or OLVFss ≤ −2.5 suggest the subject is osteoporotic, and a single collapse grade (≥ 2/3 height loss) OLVF or OLVFss ≤ −3 meets osteoporosis diagnosis criterion. The results highlight the difficulty of diagnosing osteoporotic vertebral fractures among Chinese older men.

7.
Curr Psychol ; : 1-14, 2022 Nov 24.
Article in English | MEDLINE | ID: mdl-36468162

ABSTRACT

Social media are often believed to distract adolescents' attention. While existing research has shown that some adolescents experience more social media-related distraction than others, the explanations for these differences remain largely unknown. Based on Self-Determination Theory, this preregistered study investigated two social connectivity factors (fear of missing out [FoMO] and friendship accessibility expectations) and two disconnectivity factors (self-control strategies and parental restrictions) that may explain heterogeneity in social media-related distraction. We used data collected through a measurement burst design, consisting of a three-week experience sampling method study among 300 adolescents (21,970 assessments) and online surveys. Using N = 1 analyses, we found that most adolescents (77%) experienced social media-related distraction. Contrary to expectations, none of the connectivity or disconnectivity factors explained differences in social media-related distraction. The findings indicate that social media are a powerful distractor many adolescents seem to struggle with.

8.
Media Psychol ; 25(6): 797-813, 2022.
Article in English | MEDLINE | ID: mdl-36330149

ABSTRACT

Humorous media entertainment frequently punctuates the everyday lives of adolescents. Theorists have suggested that this exposure may impact behavior, particularly real-life aggression. Specifically, exposure to prosocial (coping) humor in media entertainment is posited to decrease aggression, whereas the reverse has been argued for exposure to antisocial (disparaging and slapstick) humor. Despite these suppositions, little empirical evidence about this relationship exists. To fill this gap, this study employed a cohort-sequential design using latent growth curve models to estimate the (co-)development of adolescents' preferences for television shows featuring disparaging, slapstick, and coping humor and aggression from age 10 to 17. Results showed that at the onset of adolescence, especially boys had a higher preference for shows with disparaging and slapstick humor than with coping humor. However, over the course of adolescence, boys' and girls' preferences for shows with coping humor increased, while especially girls' preferences for shows with disparaging and slapstick humor decreased. These preferences were unrelated to adolescents' aggression. Our findings provide an important addition to the ongoing media effects debate. Taken together, they offer room for optimism and point toward an increased focus on the potential positive rather than the negative sides of humor in the lives of young people.

10.
Sci Rep ; 12(1): 7611, 2022 05 09.
Article in English | MEDLINE | ID: mdl-35534600

ABSTRACT

Research agrees that self-reported measures of time spent with social media (TSM) show poor convergent validity, because they correlate modestly with equivalent objective digital trace measures. This experience sampling study among 159 adolescents (12,617 self-reports) extends this work by examining the comparative predictive validity of self-reported and digital trace measures of TSM, that is, the extent to which self-reported and digital trace measures of TSM correspond in their effects on self-esteem, well-being, and friendship closeness. Using an N = 1 method of analysis, we investigated the correspondence on a between-person, within-person, and person-specific level. Although our results confirmed the poor convergent validity of self-reported TSM reported earlier, we found that self-reports of TSM had comparable predictive validity to digital trace measures on all three levels. Because comparative predictive validity of self-reported TSM is crucial for investigating social media effects, our results have important implications for future research using self-reported TSM.


Subject(s)
Ecological Momentary Assessment , Social Media , Adolescent , Friends , Humans , Self Concept , Self Report
11.
Quant Imaging Med Surg ; 12(3): 2090-2105, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35284274

ABSTRACT

For the MrOS (Hong Kong) and MsOS (Hong Kong) baseline (BL) studies, community-dwelling 2,000 Chinese men (mean age: 72.3 years) and 2,000 Chinese women (mean age: 72.5 years) were recruited from 2001 to 2003. These two studies have spanned two decades till now. This review summarizes our spine radiograph results. Senile and post-menopausal osteoporosis were associated with intervertebral disc volume reduction; and in women, menopause accelerates disc degeneration. Elderly women's osteoporotic vertebral fracture (OVF) prevalence was double of that of elderly men. For year-4 follow-up (FU), male participants with BL OVF had little increased risk for further OVF. In our study comparing OVF rates in age-matched Hong Kong Chinese women and Italian Caucasian women (mean age: 74.1 years), endplate and/or cortex fracture (ECF) prevalence was 26% for Chinese and 47% for Italian. OVF with ≥40% vertebral height loss was recorded among 9.5% of the Chinese subjects while among 26% of the Italian subjects. OVFs in Italian subjects were more likely to be multiple and generally severer. Clinical spine fractures were recorded 133 cases/100,000 person-years in MrOS (Hong Kong) participants and 273 cases/100,000 person-years in MsOS (Hong Kong) participants. Literature review suggests the clinical vertebral fracture rates among elderly Hong Kong Chinese subjects are approximately half of those of American, Australian, and Canadian subjects. Data synthesis suggests elderly Caucasians have a higher degenerative spondylolisthesis prevalence, being approximately 70% higher than that of elderly Hong Kong Chinese. Literature review of other authors' publications shows, compared with Caucasians, Chinese have a much lower incident rate of back pain. We conclude that elderly Chinese have a generally healthier spine relative to elderly Caucasians.

13.
Curr Opin Psychol ; 45: 101294, 2022 06.
Article in English | MEDLINE | ID: mdl-35016087

ABSTRACT

Research into the impact of social media use (SMU) on well-being (e.g., happiness) and ill-being (e.g., depression) has exploded over the past few years. From 2019 to August 2021, 27 reviews have been published: nine meta-analyses, nine systematic reviews, and nine narrative reviews, which together included hundreds of empirical studies. The aim of this umbrella review is to synthesize the results of these meta-analyses and reviews. Even though the meta-analyses are supposed to rely on the same evidence base, they yielded disagreeing associations with well- and ill-being, especially for time spent on SM, active SMU, and passive SMU. This umbrella review explains why their results disagree, summarizes the gaps in the literature, and ends with recommendations for future research.


Subject(s)
Social Media , Happiness , Humans
14.
Curr Opin Psychol ; 44: 58-68, 2022 04.
Article in English | MEDLINE | ID: mdl-34563980

ABSTRACT

Literature reviews on how social media use affects adolescent mental health have accumulated at an unprecedented rate of late. Yet, a higher-level integration of the evidence is still lacking. We fill this gap with an up-to-date umbrella review, a review of reviews published between 2019 and mid-2021. Our search yielded 25 reviews: seven meta-analyses, nine systematic, and nine narrative reviews. Results showed that most reviews interpreted the associations between social media use and mental health as 'weak' or 'inconsistent,' whereas a few qualified the same associations as 'substantial' and 'deleterious.' We summarize the gaps identified in the reviews, provide an explanation for their diverging interpretations, and suggest several avenues for future research.


Subject(s)
Social Media , Adolescent , Humans , Mental Health , Meta-Analysis as Topic , Review Literature as Topic , Social Networking
15.
Ear Hear ; 43(3): 1013-1022, 2022.
Article in English | MEDLINE | ID: mdl-34759206

ABSTRACT

OBJECTIVES: The objective of this study was to evaluate the influence of music versus speech on a listener's signal-to-noise ratio (SNR) preferences when listening in a noise background. SNR preferences were quantified using acceptable noise level (ANL) and preferred SNR metrics. The measurement paradigm for ANL allows the listener to adjust the level of background noise while listening to the target at their most comfortable loudness level. A higher ANL indicates less tolerance for noise and a lower ANL indicates high tolerance for noise. The preferred SNR is simply the SNR the listener prefers when attending to a target in a fixed-amount (level) of background noise. In contrast to the ANL, the listener does not have control over the noise. Rather, they are only able to manipulate the target level. The first aim of the study was to determine if listeners' tolerances for noise, quantified using the ANL, when listening to music is different from that when listening to speech. The second aim of the study was to determine if listeners' tolerances for noise, quantified using their preferred SNR, when listening to music is different from that when listening to speech. The third aim of the study was to quantify the relationship between ANL and preferred SNR. DESIGN: Ninety-nine normal-hearing, native-English speakers participated in this study. The ANL and preferred SNR were measured for speech and music targets. Music targets included two variations (with lyrics and without lyrics) of the song "Rocky Top." Measurements were made in the sound field at 0° azimuth, 1.5 m from a loud speaker. For both ANL and preferred SNR, targets were presented in 12-talker babble noise. The level of the noise was adjusted by the listener during ANL measurement but was fixed in level during the preferred SNR measurement (75 dB A). Repeated-measures analysis of variance was performed to identify any significant effect of target on the ANL and preferred SNR. Correlation analysis was performed to evaluate the relationship between ANL and preferred SNR. RESULTS: Findings demonstrate a significant effect of target on ANL and preferred SNR. ANLs were highest for speech (mean = 7.2 dB), followed by music with lyrics (6.1 dB), and music without lyrics (2.5 dB). Preferred SNRs were highest for music with lyrics (mean = 2.3 dB), followed by speech (1.2 dB), and music without lyrics (-0.1 dB). A listener's ANL for a given target was strongly correlated with their ANL for a different target (the same was true for preferred SNR); however, ANL for a given target was not a statistically significant predictor of preferred SNR for the same target. CONCLUSIONS: When listening in a background of noise, the listener's tolerance for noise depends on the target to which they are attending, whether music or speech. This dependence is especially evident for ANL measures, and less so for preferred SNR measures. Despite differences in ANL and preferred SNR across targets, a listener's ANL and preferred SNR for one target predicts their ANL and preferred SNR, respectively, for a different target. The lack of correlation between ANL and preferred SNR suggests different mechanisms underly these listener-preference metrics.


Subject(s)
Music , Speech Perception , Auditory Perception , Humans , Noise , Signal-To-Noise Ratio , Speech
16.
Sci Rep ; 11(1): 21176, 2021 10 27.
Article in English | MEDLINE | ID: mdl-34707197

ABSTRACT

Who benefits most from using social media is an important societal question that is centered around two opposing hypotheses: the rich-get-richer versus the poor-get-richer hypothesis. This study investigated the assumption that both hypotheses may be true, but only for some socially rich and some socially poor adolescents and across different time intervals. We employed a state-of-the-art measurement burst design, consisting of a three-week experience sampling study and seven biweekly follow-up surveys. Person-specific analyses of more than 70,000 observations from 383 adolescents revealed that 12% of the socially rich adolescents (high in friendship support or low in loneliness) felt closer to their friends after using social media, as opposed to about 25% of the socially poor adolescents (low in friendship support or high in loneliness). However, only 1 to 6% of all adolescents (socially rich and poor) felt closer both in the short- and longer-term. These results indicate that the rich-get-richer and the poor-get-richer hypotheses can hold both, but for different adolescents.


Subject(s)
Adolescent Behavior , Friends/psychology , Social Behavior , Social Media/statistics & numerical data , Adolescent , Female , Humans , Internet Use/statistics & numerical data , Loneliness , Male
17.
Dev Psychol ; 57(2): 309-323, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33539132

ABSTRACT

The formation and maintenance of friendship closeness is an important developmental task in adolescence. To obtain insight in real-time processes that may underly the development of friendship closeness in middle adolescence, this preregistered experience sampling study [ESM] investigated the effects of social media use on friendship closeness. The study was conducted among 387 adolescents (54% girls; Mage = 14.11 years; 96% Dutch) from different educational tracks (44% lower prevocational secondary education, 31% intermediate general secondary education, 26% academic preparatory education). Adolescents reported six times per day for 3 weeks on their Instagram, WhatsApp, and Snapchat use in the previous hour and their momentary experiences of friendship closeness (126 assessments; 34,930 observations). Multilevel analyses revealed positive between-person associations of friendship closeness with general WhatsApp use and Instagram use with close friends. In contrast, at the within-person level, we found small negative overall associations of general WhatsApp use and Instagram use (with and without close friends) with friendship closeness. However, there was large heterogeneity in the person-specific effect sizes of the within-person associations of social media use with friendship closeness. For example, person-specific effect sizes of the association of Instagram use with close friends with friendship closeness ranged from ß = -.745 to ß = .697. These results underline the importance of acknowledging person-specific effects in developmental and media effect theories. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Subject(s)
Adolescent Behavior , Social Media , Adolescent , Ecological Momentary Assessment , Female , Friends , Humans , Interpersonal Relations , Male
18.
J Gastrointest Surg ; 25(2): 351-356, 2021 02.
Article in English | MEDLINE | ID: mdl-33443690

ABSTRACT

INTRODUCTION: An increased transdiaphragmatic pressure gradient (TGP) is a main element for distal gastroesophageal reflux disease (GERD). The role of TGP for proximal reflux is still unclear. This study aims to evaluate the presence, severity, and importance of proximal reflux in relationship to the TGP, comparing healthy volunteers, obese individuals, and patients with chronic obstructive pulmonary disease (COPD). METHODS: We studied 114 individuals comprising 19 healthy lean volunteers, 47 obese individuals (mean body mass index 45 ± 7 kg/m2), and 48 patients with COPD. All patients underwent high-resolution manometry and dual-channel esophageal pH monitoring. Esophageal motility, thoracic pressure (TP), abdominal pressure (AP), TGP, DeMeester score, and % of proximal acid exposure time (pAET) were recorded. RESULTS: Pathologic distal GERD was found in 0, 44, and 57% of the volunteers, obese, and COPD groups, respectively. pAET was similar among groups, only higher for obese individuals GERD + as compared to obese individuals GERD - and COPD GERD -. pAET did not correlate with any parameter in healthy individuals, but it correlated with AP in the obese, TP in the COPD individuals, and TGP and DeMeester score in both groups. When all individuals were analyzed as a total, pAET correlated with AP, TGP, and DeMeester score. DeMeester score was the only independent variable that correlated with pAET. CONCLUSIONS: Our results show that (a) TGP is an important mechanism associated with distal esophageal acid exposure and this fact is linked with proximal acid exposure and (b) obesity and COPD both seem to be primary causes for GERD but not directly for proximal reflux.


Subject(s)
Esophagitis, Peptic , Gastroesophageal Reflux , Esophageal pH Monitoring , Gastroesophageal Reflux/etiology , Humans , Manometry
19.
J Public Health Manag Pract ; 27(2): 117-124, 2021.
Article in English | MEDLINE | ID: mdl-31738191

ABSTRACT

CONTEXT: Worksites can serve as community sites for local health jurisdictions (LHJs) to assist with implementation of evidence-based interventions (EBIs) to prevent and control chronic diseases. OBJECTIVE: To assess the feasibility and effectiveness of using LHJ staff to disseminate Connect to Wellness (CtW), an effective dissemination package for increasing implementation of EBIs for chronic disease control by small worksites. DESIGN: Single-arm, multisite intervention trial, with measurement at baseline, after 6 months of intervention, and after a maintenance period of 6 months. SETTING: Six geographically dispersed counties in Washington State. Target worksites had 20 to 250 employees. PARTICIPANTS: Nine staff members from 6 LHJs delivered CtW to 35 worksites. INTERVENTION: Connect to Wellness seeks to increase worksites' implementation of 14 EBIs classified as communication, policy, or program approaches to increasing 4 behaviors: cancer screening, healthy eating, physical activity, and tobacco cessation. MAIN OUTCOME MEASURE: Evidence-based intervention implementation measured on a scale from 0% to 100%. RESULTS: Participating worksites showed a significant increase (P < .001, t test) in total mean implementation scores from baseline (33%) to 6-month follow-up (47%). Increases in implementation for communications, policy, healthy eating, and tobacco EBIs were statistically significant at 6 months and maintained at 12 months. Increased implementation at 6 months of a group physical activity program was not sustained after the program became unavailable, and total implementation scores at 12 months (38%) showed little change from baseline. CONCLUSIONS: Local health jurisdiction-delivered CtW increased worksites' implementation of EBIs at 6 months, and increased implementation in communication, policy, healthy eating, and tobacco was maintained at 12 months. This package, delivered by LHJ staff working part-time on CtW, was nearly as successful as prior delivery by staff working full-time on CtW.


Subject(s)
Health Promotion , Workplace , Diet, Healthy , Exercise , Humans , Washington
20.
Biochemistry (Mosc) ; 85(8): 920-929, 2020 Aug.
Article in English | MEDLINE | ID: mdl-33045952

ABSTRACT

Unlike the OGDH-encoded 2-oxoglutarate dehydrogenase (OGDH), which is an essential enzyme present in all animal tissues, expression of the DHTKD1-encoded isoenzyme, 2-oxoadipate dehydrogenase (OADH), depends on a number of factors, and mutant DHTKD1 phenotypes are rarely manifested. Physiological significance of OADH is also obscured by the fact that both isoenzymes transform 2-oxoglutarate and 2-oxoadipate. By analogy with other members of the 2-oxo acid dehydrogenases family, OADH is assumed to be a component of the multienzyme complex that catalyzes oxidative decarboxylation of 2-oxoadipate. This study aims at molecular characterization of OADH from animal tissues. Phylogenetic analysis of 2-oxo acid dehydrogenases reveals OADH only in animals and Dictyostelium discoideum slime mold, within a common branch with bacterial OGDH. Examination of partially purified animal OADH by immunoblotting and mass spectrometry identifies two OADH isoforms with molecular weights of about 130 and 70 kDa. These isoforms are not observed upon the expression of human DHTKD1 protein in either bacterial or yeast system, where the synthesized OADH is of expected molecular weight (about 100 kDa). Thus, the OADH isoforms present in animal tissues, may result from the animal-specific regulation of the DHTKD1 expression and/or posttranslational modifications of the encoded protein. Mapping of the peptides identified in the OADH preparations, onto the protein structure suggests that the 70-kDa isoform is truncated at the N-terminus, but retains the active site. Since the N-terminal domain of OGDH is required for the formation of the multienzyme complex, it is possible that the 70-kDa isoform catalyzes non-oxidative transformation of dicarboxylic 2-oxo acids that does not require the multienzyme structure. In this case, the ratio of the OADH isoforms in animal tissues may correspond to the ratio between the oxidative and non-oxidative decarboxylation of 2-oxoadipate.


Subject(s)
Brain/metabolism , Escherichia coli/metabolism , Ketoglutarate Dehydrogenase Complex/chemistry , Liver/metabolism , Myocardium/metabolism , Saccharomyces cerevisiae/metabolism , Animals , Catalytic Domain , Dictyostelium/genetics , Dictyostelium/metabolism , Escherichia coli/genetics , Humans , Isoenzymes/chemistry , Isoenzymes/metabolism , Ketoglutarate Dehydrogenase Complex/genetics , Ketoglutarate Dehydrogenase Complex/metabolism , Male , Oxidation-Reduction , Phylogeny , Rats , Rats, Wistar , Saccharomyces cerevisiae/genetics
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