| 27131. |
- Diller, Gerhard-Paul, et al.
(författare)
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Exercise intolerance in adult congenital heart disease : comparative severity, correlates, and prognostic implication.
- 2005
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Ingår i: Circulation. - 0009-7322 .- 1524-4539. ; 112:6, s. 828-35
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Although some patients with adult congenital heart disease (ACHD) report limitations in exercise capacity, we hypothesized that depressed exercise capacity may be more widespread than superficially evident during clinical consultation and could be a means of assessing risk.METHODS AND RESULTS: Cardiopulmonary exercise testing was performed in 335 consecutive ACHD patients (age, 33+/-13 years), 40 non-congenital heart failure patients (age, 58+/-15 years), and 11 young (age, 29+/-5 years) and 12 older (age, 59+/-9 years) healthy subjects. Peak oxygen consumption (peak VO2) was reduced in ACHD patients compared with healthy subjects of similar age (21.7+/-8.5 versus 45.1+/-8.6; P<0.001). No significant difference in peak VO2 was found between ACHD and heart failure patients of corresponding NYHA class (P=NS for each NYHA class). Within ACHD subgroups, peak VO2 gradually declined from aortic coarctation (28.7+/-10.4) to Eisenmenger (11.5+/-3.6) patients (P<0.001). Multivariable correlates of peak VO2 were peak heart rate (r=0.33), forced expiratory volume (r=0.33), pulmonary hypertension (r=-0.26), gender (r=-0.23), and body mass index (r=-0.19). After a median follow-up of 10 months, 62 patients (18.5%) were hospitalized or had died. On multivariable Cox analysis, peak VO2 predicted hospitalization or death (hazard ratio, 0.937; P=0.01) and was related to the frequency and duration of hospitalization (P=0.01 for each).CONCLUSIONS: Exercise capacity is depressed in ACHD patients (even in allegedly asymptomatic patients) on a par with chronic heart failure subjects. Lack of heart rate response to exercise, pulmonary arterial hypertension, and impaired pulmonary function are important correlates of exercise capacity, as is underlying cardiac anatomy. Poor exercise capacity identifies ACHD patients at risk for hospitalization or death.
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| 27132. |
- Dilliott, Allison A., et al.
(författare)
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Clinical testing panels for ALS : global distribution, consistency, and challenges
- 2023
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Ingår i: Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration. - : Taylor & Francis. - 2167-8421 .- 2167-9223. ; 24:5-6, s. 420-435
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Tidskriftsartikel (refereegranskat)abstract
- Objective: In 2021, the Clinical Genome Resource (ClinGen) amyotrophic lateral sclerosis (ALS) spectrum disorders Gene Curation Expert Panel (GCEP) was established to evaluate the strength of evidence for genes previously reported to be associated with ALS. Through this endeavor, we will provide standardized guidance to laboratories on which genes should be included in clinical genetic testing panels for ALS. In this manuscript, we aimed to assess the heterogeneity in the current global landscape of clinical genetic testing for ALS.Methods: We reviewed the National Institutes of Health (NIH) Genetic Testing Registry (GTR) and members of the ALS GCEP to source frequently used testing panels and compare the genes included on the tests.Results: 14 clinical panels specific to ALS from 14 laboratories covered 4 to 54 genes. All panels report on ANG, SOD1, TARDBP, and VAPB; 50% included or offered the option of including C9orf72 hexanucleotide repeat expansion (HRE) analysis. Of the 91 genes included in at least one of the panels, 40 (44.0%) were included on only a single panel. We could not find a direct link to ALS in the literature for 14 (15.4%) included genes.Conclusions: The variability across the surveyed clinical genetic panels is concerning due to the possibility of reduced diagnostic yields in clinical practice and risk of a missed diagnoses for patients. Our results highlight the necessity for consensus regarding the appropriateness of gene inclusions in clinical genetic ALS tests to improve its application for patients living with ALS and their families.
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| 27133. |
- Dimberg, A., et al.
(författare)
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Cancer angiogenesis and vasculogenesis
- 2014
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Ingår i: Pathobiology of human disease. - : Academic Press. - 9780123864567 - 9780123864574 ; , s. 403-411
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Bokkapitel (refereegranskat)abstract
- A growing tumor is dependent on developing a functioning vasculature. Blood vessels can be formed through de novo differentiation from endothelial progenitor cells in the process of vasculogenesis or by sprouting or splitting from existing blood vessels in the process of angiogenesis. In this article, these processes are discussed in detail with a special focus on the signaling events that guide the development of a tumor vasculature. Preventing angiogenesis is a potential way of treating cancer, and many antiangiogenic substances have entered the clinic and are used as therapeutic options for certain cancers.
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| 27134. |
- Dimitrakopoulou, Vasiliki I., et al.
(författare)
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Interactions between genome-wide significant genetic variants and circulating concentrations of 25-Hydroxyvitamin D in relation to prostate cancer risk in the National Cancer Institute BPC3
- 2017
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Ingår i: American Journal of Epidemiology. - : Oxford University Press (OUP). - 0002-9262 .- 1476-6256. ; 185:6, s. 452-464
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have identified over 100 single nucleotide polymorphisms (SNPs) associated with prostate cancer. However, information on the mechanistic basis for some associations is limited. Recent research has been directed towards the potential association of Vitamin D concentrations and prostate cancer, but little is known about whether the aforementioned genetic associations are modified by Vitamin D. We investigated the associations of 46 GWAS-identified SNPs, circulating concentrations of 25-hydroxyVitamin D (25 (OH)D), and prostate cancer (3,811 cases, 511 of whom died from the disease, compared with 2,980 controls- from 5 cohort studies that recruited participants over several periods beginning in the 1980s). We used logistic regression models with data from the National Cancer Institute Breast and Prostate Cancer Cohort Consortium (BPC3) to evaluate interactions on the multiplicative and additive scales. After allowing for multiple testing, none of the SNPs examined was significantly associated with 25(OH)D concentration, and the SNP-prostate cancer associations did not differ by these concentrations. A statistically significant interaction was observed for each of 2 SNPs in the 8q24 region (rs620861 and rs16902094), 25(OH)D concentration, and fatal prostate cancer on both multiplicative and additive scales (P ≥ 0.001). We did not find strong evidence that associations between GWASidentified SNPs and prostate cancer are modified by circulating concentrations of 25(OH)D. The intriguing interactions between rs620861 and rs16902094, 25(OH)D concentration, and fatal prostate cancer warrant replication.
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| 27135. |
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| 27136. |
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| 27137. |
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| 27138. |
- Dimitriou, Michael
(författare)
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Enhanced Muscle Afferent Signals during Motor Learning in Humans
- 2016
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 26:8, s. 1062-1068
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Tidskriftsartikel (refereegranskat)abstract
- Much has been revealed concerning human motor learning at the behavioral level [1, 2], but less is known about changes in the involved neural circuits and signals. By examining muscle spindle responses during a classic visuomotor adaptation task [3-6] performed by fully alert humans, I found substantial modulation of sensory afferent signals as a function of adaptation state. Specifically, spindle control was independent of concurrent muscle activity but was specific to movement direction (representing muscle lengthening versus shortening) and to different stages of learning. Increased spindle afferent responses to muscle stretch occurring early during learning reflected individual error size and were negatively related to subsequent antagonist activity (i.e., 60-80 ms thereafter). Relative increases in tonic afferent output early during learning were predictive of the subjects' adaptation rate. I also found that independent spindle control during sensory realignment (the "washout" stage) induced afferent signal "linearization" with respect to muscle length (i.e., signals were more tuned to hand position). The results demonstrate for the first time that motor learning also involves independent and state-related modulation of sensory mechanoreceptor signals. The current findings suggest that adaptive motor performance also relies on the independent control of sensors, not just of muscles. I propose that the "gamma" motor system innervating spindles acts to facilitate the acquisition and extraction of task-relevant information at the early stages of sensorimotor adaptation. This designates a more active and targeted role for the human proprioceptive system during motor learning.
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| 27139. |
- Dimitriou, Michael
(författare)
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Human Muscle Spindle Sensitivity Reflects the Balance of Activity between Antagonistic Muscles
- 2014
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Ingår i: Journal of Neuroscience. - 0270-6474 .- 1529-2401. ; 34:41, s. 13644-13655
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Tidskriftsartikel (refereegranskat)abstract
- Muscle spindles are commonly considered as stretch receptors encoding movement, but the functional consequence of their efferent control has remained unclear. The "alpha-gamma coactivation" hypothesis states that activity in a muscle is positively related to the output of its spindle afferents. However, in addition to the above, possible reciprocal inhibition of spindle controllers entails a negative relationship between contractile activity in one muscle and spindle afferent output from its antagonist. By recording spindle afferent responses from alert humans using microneurography, I show that spindle output does reflect antagonistic muscle balance. Specifically, regardless of identical kinematic profiles across active finger movements, stretch of the loaded antagonist muscle (i.e., extensor) was accompanied by increased afferent firing rates from this muscle compared with the baseline case of no constant external load. In contrast, spindle firing rates from the stretching antagonist were lowest when the agonist muscle powering movement (i.e., flexor) acted against an additional resistive load. Stepwise regressions confirmed that instantaneous velocity, extensor, and flexor muscle activity had a significant effect on spindle afferent responses, with flexor activity having a negative effect. Therefore, the results indicate that, as consequence of their efferent control, spindle sensitivity (gain) to muscle stretch reflects the balance of activity between antagonistic muscles rather than only the activity of the spindle-bearing muscle.
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| 27140. |
- Dimitriou, Michael, et al.
(författare)
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Human muscle spindles act as forward sensory models
- 2010
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 20:19, s. 1763-1767
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Tidskriftsartikel (refereegranskat)abstract
- Modern theories of motor control incorporate forward models that combine sensory information and motor commands to predict future sensory states. Such models circumvent unavoidable neural delays associated with on-line feedback control. Here we show that signals in human muscle spindle afferents during unconstrained wrist and finger movements predict future kinematic states of their parent muscle. Specifically, we show that the discharges of type Ia afferents are best correlated with the velocity of length changes in their parent muscles approximately 100-160 ms in the future and that their discharges vary depending on motor sequences in a way that cannot be explained by the state of their parent muscle alone. We therefore conclude that muscle spindles can act as "forward sensory models": they are affected both by the current state of their parent muscle and by efferent (fusimotor) control, and their discharges represent future kinematic states. If this conjecture is correct, then sensorimotor learning implies learning how to control not only the skeletal muscles but also the fusimotor system.
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