scholarly journals Short-Long Heart Rate Variation Increases Dispersion of Action Potential Duration in Long QT Type 2 Transgenic Rabbit Model

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tae Yun Kim ◽  
Paul Jeng ◽  
JungMin Hwang ◽  
Zachary Pfeiffer ◽  
Divyang Patel ◽  
...  
Keyword(s):  
Short Term Memory ◽  
Rabbit Model ◽  
Polymorphic Ventricular Tachycardia ◽  
Rate Variation ◽  
Short Term ◽  
Long Qt ◽  
Term Memory ◽  
Transgenic Rabbit ◽  
Cycle Lengths

Abstract The initiation of polymorphic ventricular tachycardia in long QT syndrome type 2 (LQT2) has been associated with a characteristic ECG pattern of short-long RR intervals. We hypothesize that this characteristic pattern increases APD dispersion in LQT2, thereby promoting arrhythmia. We investigated APD dispersion and its dependence on two previous cycle lengths (CLs) in transgenic rabbit models of LQT2, LQT1, and their littermate controls (LMC) using random stimulation protocols. The results show that the short-long RR pattern was associated with a larger APD dispersion in LQT2 but not in LQT1 rabbits. The multivariate analyses of APD as a function of two previous CLs (APDn = C + α1CLn−1 + α2CLn−2) showed that α1 (APD restitution slope) is largest and heterogeneous in LQT2 but uniform in LQT1, enhancing APD dispersion under long CLn−1 in LQT2. The α2 (short-term memory) was negative in LQT2 while positive in LQT1, and the spatial pattern of α1 was inversely correlated to α2 in LQT2, which explains why a short-long combination causes a larger APD dispersion in LQT2 but not in LQT1 rabbits. In conclusion, short-long RR pattern increased APD dispersion only in LQT2 rabbits through heterogeneous APD restitution and the short-term memory, underscoring the genotype-specific triggering of arrhythmias in LQT syndrome.

scholarly journals Alternating Cycle Lengths Increases Dispersion of Action Potential Durations (APD) in Transgenic Rabbit Model of Long QT Syndrome Type 2

2012 ◽  
Vol 102 (3) ◽  
pp. 539a-540a
Author(s):  
Tae Yun Kim ◽  
Paul Jeng ◽  
Chantel Taylor ◽  
JungMin Hwang ◽  
Xuwen Peng ◽  
...  
Keyword(s):  
Action Potential ◽  
Long Qt Syndrome ◽  
Rabbit Model ◽  
Syndrome Type ◽  
Long Qt ◽  
Transgenic Rabbit ◽  
Cycle Lengths ◽  
Qt Syndrome

scholarly journals Origin of complex behaviour of spatially discordant alternans in a transgenic rabbit model of type 2 long QT syndrome

2009 ◽  
Vol 587 (19) ◽  
pp. 4661-4680 ◽  
Author(s):  
Ohad Ziv ◽  
Eduardo Morales ◽  
Yoon-kyu Song ◽  
Xuwen Peng ◽  
Katja E. Odening ◽  
...  
Keyword(s):  
Long Qt Syndrome ◽  
Rabbit Model ◽  
Long Qt ◽  
Complex Behaviour ◽  
Transgenic Rabbit ◽  
Qt Syndrome

scholarly journals Complex excitation dynamics underlie polymorphic ventricular tachycardia in a transgenic rabbit model of long QT syndrome type 1

Heart Rhythm ◽  
2015 ◽  
Vol 12 (1) ◽  
pp. 220-228 ◽  
Author(s):  
Tae Yun Kim ◽  
Yukiko Kunitomo ◽  
Zachary Pfeiffer ◽  
Divyang Patel ◽  
Jungmin Hwang ◽  
...  
Keyword(s):  
Ventricular Tachycardia ◽  
Long Qt Syndrome ◽  
Rabbit Model ◽  
Polymorphic Ventricular Tachycardia ◽  
Syndrome Type ◽  
Long Qt ◽  
Transgenic Rabbit ◽  
Qt Syndrome ◽  
Excitation Dynamics

scholarly journals Effect of short-term memory and working memory in diabetes with comorbidities condition

2020 ◽  
Vol 11 (4) ◽  
pp. 5367-5372
Author(s):  
Anand Vijayakumar P R ◽  
Seema A ◽  
Kokul Rajan P
Keyword(s):  
Working Memory ◽  
Cognitive Decline ◽  
Short Term Memory ◽  
Hippocampal Sclerosis ◽  
Diabetes Patient ◽  
Diabetic Patients ◽  
Short Term ◽  
Term Memory ◽  
Short Period

Cognitive function refers to the ability of humans to function normally which includes physical as well as mental interpretation like ability to focus, concentrate, learn, plan, determine, execute, manipulate and problem solving. Etiologic of cognitive dysfunction includes AD, depression, anxiety and vascular dementia, hippocampal sclerosis etc., Diabetes associated with cognitive decline are related to short fall of learning and memory. Cognitive impairment/dysfunction in diabetic patients has been divided into three stages, stage one, stage two and stage three. Stage one, occur in all groups of different ages and it is characterized by mild and subtle changes in cognition. Deficit in short-term memory and working memory leads to major problems like Alzheimer disease and dementia. The pathophysiology of cognitive decline associated involves microvascular injury, hyperglycaemia, insulin resistance and oxidative stress. Diabetes associated with comorbidities condition leads to decrease in short-term memory and working memory. From this review we observed short term memory retains small amount of data in cognizance which are readily available state for short period of time whereas working memory manipulates the information through visual and auditory storage and it is important in understanding and improving the memory. Conclusion of this review is that, there is a decrease in short-term memory and working memory in type 2 diabetes patient condition. But there is no evidence of which type comorbidity condition affects more in short-term memory and working memory. So, further research study to be carried out.

scholarly journals Spatial heterogeneity of the restitution portrait in rabbit epicardium

2007 ◽  
Vol 292 (3) ◽  
pp. H1568-H1578 ◽  
Author(s):  
Ann M. Pitruzzello ◽  
Wanda Krassowska ◽  
Salim F. Idriss
Keyword(s):  
Spatial Heterogeneity ◽  
Time Constant ◽  
Short Term Memory ◽  
Zealand White Rabbit ◽  
Electrical Stability ◽  
Short Term ◽  
Term Memory ◽  
Rate Dependent ◽  
Spatial Differences ◽  
Cycle Lengths

Spatial heterogeneity of repolarization can provide a substrate for reentry to occur in myocardium. This heterogeneity may result from spatial differences in action potential duration (APD) restitution. The restitution portrait (RP) measures many aspects of rate-dependent restitution: the dynamic restitution curve (RC), S1-S2 RC, and short-term memory response. We used the RP to characterize epicardial patterns of spatial heterogeneity of restitution that were repeatable across animals. New Zealand White rabbit ventricles were paced from the epicardial apex, midventricle, or base, and optical action potentials were recorded from the same three regions. A perturbed downsweep pacing protocol was applied that measured the RP over a range of cycle lengths from 1,000 to 140 ms. The time constant of short-term memory measured close to the stimulus was dependent on location. In the midventricle the mean time constant was 19.1 ± 1.1 s, but it was 39% longer at the apex ( P < 0.01) and 23% longer at the base ( P = 0.03). The S1-S2 RC slope was dependent on pacing site ( P = 0.015), with steeper slope when pacing from the apex than from the base. There were no significant repeatable spatial patterns in steady-state APD at all cycle lengths or in dynamic RC slope. These results indicate that transient patterns of epicardial heterogeneity of APD may occur after a change in pacing rate. Thus it may affect cardiac electrical stability at the onset of a tachycardia or during a series of ectopic beats. Differences in restitution with respect to pacing site suggest that vulnerability may be affected by the location of reentry or ectopic foci.

scholarly journals Association of duration of type 2 diabetes with short term and working memory

2017 ◽  
Vol 5 (11) ◽  
pp. 4724
Author(s):  
Upneet Bedi ◽  
Bavneet Kaur Dang
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Working Memory ◽  
Type 2 Diabetes Mellitus ◽  
Short Term Memory ◽  
Diabetic Patients ◽  
Short Term ◽  
Term Memory ◽  
Memory Status

Background: Type 2 diabetes mellitus has deleterious effects on brain resulting in loss of short term memory and working memory in elderly and poorly controlled diabetic patients. Less attention has been given to the effect of diabetes on cognitive functions. Hence, the study was undertaken to study the status of short term and working memory in type 2 diabetes mellitus and to correlate it with the duration of diabetes.Methods: Study was conducted in Punjab Institute of Medical Sciences, Jalandhar, India, on 100 diabetic patients in the age group of 40-60 years. Short term memory and working memory was assessed using 4 memory tests. AVLT and VFT for short term memory and WDST and VST for working memory. The results expressed in average of total scores. One-way ANOVA followed by post hoc (t) test were used for statistical analysis.Results: Short term memory and working memory status was negatively correlated with duration of diabetes. Diabetics more than 55 years showed greater cognitive decline compared to younger age group.Conclusions: The short term and the working memory status decreased significantly in diabetic patients, which may be due to age of onset, duration, vascular dementia, hyperglycemia or hypoglycemia. These effects observed that duration, sex, age and blood glucose levels are of clinical importance as short term and working memory loss could have important practical implications for daily activities.

scholarly journals Two New Diterpenoids from Biscogniauxia sp. and Their Activities

2021 ◽  
Vol 9 ◽  
Author(s):  
Huan Zhao ◽  
Yue Liu ◽  
Meng Zhang ◽  
Guo-dong Chen ◽  
Dan Hu ◽  
...  
Keyword(s):  
Short Term Memory ◽  
Chemical Shifts ◽  
Cytotoxic Activities ◽  
Short Term ◽  
Memory Enhancement ◽  
Term Memory ◽  
X Ray Crystallography ◽  
Spectroscopic Analyses

Two new diterpenoids, including a seco-isopimarane type (1) and an abietane type (2), were isolated from Biscogniauxia sp. (71-10-1-1). Their structures, including absolute configurations, were elucidated by NMR spectroscopic analyses, X-ray crystallography, 13C chemical shifts calculations, and ECD calculations. This is the first report of diterpenoids from Biscogniauxia sp. Furthermore, short-term memory enhancement against Alzheimer’s disease (AD), anti-inflammatory, and cytotoxic activities of 1–2 were also evaluated. The results showed that compound 1 exhibited short-term memory enhancement activity against AD.

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