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Background: Pregnancy is a unique physiological state with systemic changes including cardiovascular, autonomic, hemodynamic and psychological. Increase in incidence of stress and depression in antenatal period has been reported. Autonomic changes in pregnancy and its dysfunction in depression are well documented. However, there is lack of evidence associating cardiovascular autonomic dysfunction to stress and depressed mood in pregnant women., Methods: In this correlation study, we assessed cardiovascular autonomic functions of 172 pregnant women using heart rate variability (HRV) and baroreflex sensitivity (BRS). The Edinburg postnatal depression scale (EPDS) was used to evaluate depressive symptoms and perceived stress scale (PSS) was used to assess stress. The HRV and BRS parameters were correlated with EPDS and PSS. Multiple regression analysis was performed for EPDS and PSS individually to study their association with cardiac autonomic functions(CAF)., Results: HRV and BRS were well correlated to EPDS and PSS scores. The depression and stress were found to be significantly associated to autonomic dysfunctions as increased sympathetic and decreased parasympathetic activity. Among various CAF parameters, LF:HF ratio and BRS were found to be significantly associated with depression and stress among these women., Conclusion: LF:HF ratio and BRS may be associated with depression during antenatal period. The depression in antenatal period may add on to cardiovascular risk in expecting mothers., (Copyright © 2020 Elsevier B.V. All rights reserved.)

It is of fundamental significance to study human brain functions using neuroimaging technologies, such as electroencephalograph (EEG) and functional magnetic resonance imaging (fMRI), in real-world tasks. The present study explores the feasibility of using EEG to identify networked brain activations when subjects perform a realistic task. To robustly identify physiologically plausible EEG patterns related to brain activations involved in the task, a novel data-driven method, i.e., time-frequency independent component analysis (tfICA), is developed to analyze high-density EEG data, which combines the time-frequency analysis and complex-valued ICA method. Six classes of independent components (ICs) of various spatio-temporal-spectral patterns were identified across subjects, relating to frontal, motor, premotor, supplementary motor, secondary somatosensory, and occipital cortices, which suggest a networked brain activation involving visual perception and processing, movement planning and execution, working memory, performance monitoring, and decision making to accomplish the task. Our results indicate that temporal patterns of these ICs are consistent, show causal relationship among them, and of significant correlation to behavioral performance data recorded in same task sessions. Furthermore, the time-on-task effect that indicates the phenomenon of mental fatigue in sustained tasks for a long duration (i.e., 1h) was observed. The present study demonstrates the capability of the tfICA method in distinguishing various brain processes from continuous EEG data obtained in a realistic task and it is thus promising to address real-world problems, such as time-on-task fatigue., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Earlier studies in this laboratory had shown that the malarial parasite can synthesize heme de novo and inhibition of the pathway leads to death of the parasite. It has been proposed that the pathway for the biosynthesis of heme in Plasmodium falciparum is unique involving three different cellular compartments, namely mitochondrion, apicoplast and cytosol. Experimental evidences are now available for the functionality and localization of all the enzymes of this pathway, except protoporphyrinogen IX oxidase (PfPPO), the penultimate enzyme. In the present study, PfPPO has been cloned, expressed and shown to be localized to the mitochondrion by immunofluorescence microscopy. Interestingly, the enzyme has been found to be active only under anaerobic conditions and is dependent on electron transport chain (ETC) acceptors for its activity. The native enzyme present in the parasite is inhibited by the ETC inhibitors, atovaquone and antimycin. Atovaquone, a well known inhibitor of parasite dihydroorotate dehydrogenase, dependent on the ETC, inhibits synthesis of heme as well in P. falciparum culture. A model is proposed to explain the ETC dependence of both the pyrimidine and heme-biosynthetic pathways in P. falciparum., (Copyright 2010 Elsevier B.V. All rights reserved.)

In the malarial parasite, enzymes of heme-biosynthetic pathway are distributed in different cellular compartments. The site of localization of ferrochelatase in the malarial parasite is crucial, since it will decide the ultimate site of heme synthesis. Earlier results have differed in terms of localization, being the mitochondrion or apicoplast and the functional enzyme has not been cloned, expressed and characterized. The present study reveals that Plasmodium falciparum ferrochelatase (PfFC) gene encodes multiple transcripts of which the one encoding the full length functional protein (PfFC) has been cloned and the recombinant protein over-expressed and purified from E. coli cells. The enzyme shows maximum activity with iron, while zinc is a poor substrate. Immunofluorescence studies with antibodies to functional ferrochelatase reveal that the native enzyme is localized to the mitochondrion of the parasite indicating that this organelle is the ultimate site of heme synthesis.