Utility of Atypical Lymphocytes and Large Immature Cells in Prediction of Dengue Severity.

Background: There is a clinical imperative to devise metrics to prognosticate dengue severity. Our objective was to determine the association between longitudinal trends in atypical lymphocytes and large immature cell count with platelet count and dengue severity. Materials and methods: Retrospective analysis of longitudinally measured clinical and hematological data from (n = 79) hospitalized dengue patients was done. Results: The cohort consisted of patients with dengue fever without warning signs (DFWOWS) (n = 40, females = 14, and age = 19.9 ± 14.6 years), dengue fever with warning signs (DFWWS) (n = 36, females = 13, and age = 16.1 ± 14.1 years) and severe dengue (n = 3, females = 2, and age = 5.3 ± 4 years). Platelet count increased at a rate of 11,524 cells/mm3/day, with a slower rate of rise as the severity increased (p = 0.001***). Concurrently hematocrit and neutrophil percentage decreased, while the lymphocyte percentage and white blood cell (WBC) count increased during the hospital stay. Every 1% increase in atypical lymphocyte count (ATY) was associated with a fall in platelet count by 16,963 cells/mm3 (p = 0.001***). A similar but weaker trend was found for large immature cells (LICs). Conclusion: The data support the usefulness of longitudinal tracking of atypical lymphocyte and large immature cell count for dengue prognosis. The time trends of the hematological parameters indicate the progression of patients from the critical to the recovery phase. How to cite this article: Peraka R, Koppula A, Muppala BS, et al. Utility of Atypical Lymphocytes and Large Immature Cells in Prediction of Dengue Severity. J Assoc Physicians India 2023;71(11):19-24.

Effects of exercise anticipation on cardiorespiratory coherence.

In this study, we explored the role of feedforward mechanisms in triggering cardiorespiratory adjustments before the onset of exercise. To isolate the feedforward aspects, we examined the effect of exercise anticipation on cardiorespiratory coherence. Twenty-nine healthy males (age = 18.8 [0.96] years) were subjected to bicycle (BE) and handgrip exercise (H) at two different intensities, viz., low and high. Bicycle exercise was performed in a unilateral (left- and right-sided) or bilateral mode, whereas handgrip was performed only in a unilateral mode. Single-lead ECG and respiratory rhythm, measured in the 5 min of anticipation phase before the onset of exercise, were used for analysis. Coherence was computed between ECG-derived instantaneous heart rate and respiratory signal. Average coherence in the high-frequency band (0.15-0.4 Hz) was used to estimate respiratory sinus arrhythmia (RSA). We found that coherence decreased with the anticipation of exercise relative to baseline (baseline = 0.54 [0.16], BE = 0.41 [0.12], H = 0.39 [0.12], p < 0.001). The decrease was greater for high intensity exercise (low = 0.42 [0.11], high = 0.37 [0.1], p < 0.001). The fall of coherence with intensity was stronger for bicycle exercise (BE: low = 0.44 [0.12], high = 0.37 [0.12], H: low = 0.4 [0.12], high = 0.37 [0.12], p = 0.00433). The expectation of bilateral exercise resulted in lower coherence compared to unilateral exercise (right-sided = 0.45 [0.16], left-sided = 0.4 [0.16], bilateral = 0.36 [0.15], unilateral vs. bilateral: p < 0.001), and the left-sided exercise had lower coherence compared to that of the right (left-sided vs. right-sided: p = 0.00925). Handgrip exercise showed similar trend (right-sided = 0.4 [0.15], left-sided = 0.37 [0.14], p = 0.0056). In conclusion, feedforward RSA adjustments in anticipation of exercise covaried with subsequent exercise-related features like intensity, muscle mass (unilateral vs. bilateral), and the exercise side (left vs. right). The left versus the right difference in coherence indicates autonomic asymmetry. Feedforward changes in RSA are like those seen during actual exercise and might facilitate the rapid phase transition between rest and exercise.

Feasibility of home-based tracking of insulin resistance from vascular stiffness estimated from the photoplethysmographic finger pulse waveform.

Objective.In this study we explored the utility of post-prandial vascular stiffness as a surrogate measure for estimating insulin resistance, which is a pre-diabetic condition.Approach.A cohort of 51 healthy young adults with varying body mass index (BMI) values was studied using fasting plasma values of insulin and glucose, fasting and post-meal finger photoplethysmography (PPG) and electrocardiogram (ECG). Insulin resistance was estimated by homeostatic model assessment for insulin resistance 2 (HOMA-IR2) using fasting plasma insulin and glucose. Vascular stiffness was estimated by reciprocal of pulse arrival time (rPAT) from ECG and finger PPG at five time points from fasting to 2 h post-oral glucose ingestion. We examined if insulin resistance correlates with meal-induced vascular stiffness changes, supporting the feasibility of using finger PPG to estimate insulin resistance.Main results.HOMA-IR2 was positively correlated with an early rise (0 to 30 min post-meal) and delayed fall (30 to 120 min post-meal) of rPAT. Correlation persisted even after the effect of BMI has been partialled out in subgroup analysis. We conclude that finger PPG-based pulse waveform and single-lead ECG has the potential to be used as a non-invasive method for the assessment of insulin resistance.Significance.As both signals, namely ECG and PPG, can be easily acquired using wearable and other low-cost sensing systems, the present study can serve as a pointer to develop accessible strategies for monitoring and longitudinal tracking of insulin resistance in health and pathophysiological states.