Altered neuroepithelial morphogenesis and migration defects in iPSC-derived cerebral organoids and 2D neural stem cells in familial bipolar disorder

Bipolar disorder (BD) is a severe mental illness that can result from neurodevelopmental aberrations, particularly in familial BD, which may include causative genetic variants. In the present study, we derived cortical organoids from BD patients and healthy (control) individuals from a clinically dense family in the Indian population. Our data reveal that the patient organoids show neurodevelopmental anomalies, including organisational, proliferation and migration defects. The BD organoids show a reduction in both the number of neuroepithelial buds/cortical rosettes and the ventricular zone size. Additionally, patient organoids show a lower number of SOX2-positive and EdU-positive cycling progenitors, suggesting a progenitor proliferation defect. Further, the patient neurons show abnormal positioning in the ventricular/intermediate zone of the neuroepithelial bud. Transcriptomic analysis of control and patient organoids supports our cellular topology data and reveals dysregulation of genes crucial for progenitor proliferation and neuronal migration. Lastly, time-lapse imaging of neural stem cells in 2D in vitro cultures reveals abnormal cellular migration in BD samples. Overall, our study pinpoints a cellular and molecular deficit in BD patient-derived organoids and neural stem cell cultures.

LSD1 Regulates Neurogenesis in Human Neural Stem Cells Through the Repression of Human-Enriched Extracellular Matrix and Cell Adhesion Genes

Neurogenesis begins with neural stem cells undergoing symmetric proliferative divisions to expand and then switching to asymmetric differentiative divisions to generate neurons in the developing brain. Chromatin regulation plays a critical role in this switch. Histone lysine-specific demethylase LSD1 demethylates H3K4me1/2 and H3K9me1/2 but the mechanisms of its global regulatory functions in human neuronal development remain unclear. We performed genome-wide ChIP-seq of LSD1 occupancy, RNA-seq, and Histone ChIP-seq upon LSD1 inhibition to identify its repressive role in human neural stem cells. Novel downstream effectors of LSD1 were identified, including the Notch signaling pathway genes and human-neural progenitor-enriched extracellular matrix (ECM) pathway/cell adhesion genes, which were upregulated upon LSD1 inhibition. LSD1 inhibition led to decreased neurogenesis, and overexpression of downstream effectors mimicked this effect. Histone ChIP-seq analysis revealed that active and enhancer markers H3K4me2, H3K4me1, and H3K9me1 were upregulated upon LSD1 inhibition, while the repressive H3K9me2 mark remained mostly unchanged. Our work identifies the human-neural progenitor-enriched ECM pathway/cell adhesion genes and Notch signaling pathway genes as novel downstream effectors of LSD1, regulating neuronal differentiation in human neural stem cells.

Regulation of chromatin accessibility and gene expression in the developing hippocampal primordium by LIM-HD transcription factor LHX2

In the mammalian cerebral cortex, the hippocampal primordium (Hcp) occupies a discrete position in the dorsal telencephalic neuroepithelium adjacent to the neocortical primordium (Ncp). We examined transcriptomic and chromatin-level features that distinguish the Hcp from the Ncp in the mouse during the early neurogenic period, embryonic day (E)12.5. ATAC-seq revealed that the Hcp was more accessible than the Ncp at this stage. Motif analysis of the differentially accessible loci in these tissues revealed LHX2 as a candidate transcription factor for modulating gene regulatory networks (GRNs). We analyzed LHX2 occupancy profiles and compared these with transcriptomic data from control and Lhx2 mutant Hcp and Ncp at E12.5. Our results revealed that LHX2 directly regulates distinct genes in the Hcp and Ncp within a set of common pathways that control fundamental aspects of development namely pluripotency, axon pathfinding, Wnt, and Hippo signaling. Loss of Lhx2 caused a decrease in accessibility, specifically in hippocampal chromatin, suggesting that this factor may play a unique role in hippocampal development. We identified 14 genes that were preferentially enriched in the Hcp, for which LHX2 regulates both chromatin accessibility and mRNA expression, which have not thus far been examined in hippocampal development. Together, these results provide mechanistic insight into how LHX2 function in the Hcp may contribute to the process by which the hippocampus acquires features distinct from the neocortex.

Combinatorial delivery of CPI444 and vatalanib loaded on PEGylated graphene oxide as an effective nanoformulation to target glioblastoma multiforme: In vitro evaluation

Glioblastoma multiforme (GBM) is known as the primary malignant and most devastating form of tumor found in the central nervous system of the adult population. The active pharmaceutical component in current chemotherapy regimens is mostly hydrophobic and poorly water-soluble, which hampers clinical implications. Nanodrug formulations using nanocarriers loaded with such drugs assisted in water dispersibility, improved cellular permeability, and drug efficacy at a low dose, thus adding to the overall practical value. Here, we successfully developed a water-dispersible and biocompatible nanocargo (GO-PEG) based on covalently modified graphene oxide (GO) with a 6-armed poly(ethylene glycol) amine dendrimer for effective loading of the two hydrophobic anticancer drug molecules, CPI444 and vatalanib. These drug molecules target adenosine receptor (A2AR), vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), and type III stem cell receptor tyrosine kinase (c-KIT), which plays a crucial role in cancers. The effective cellular delivery of the drugs when loaded on GO-PEG is attributed to the increased permeability of the drug-nanoconjugate formulation. We observed that this combinatorial drug treatment with nanocargo resulted in a significant reduction in the overall cell survival as supported by reduced calcium levels and stem cell markers such as Oct4 and Nanog, which are two of the prime factors for GBM stem cell proliferation. Furthermore, reduced expression of CD24 upon treatment with nanoformulation impeded cellular migration. Cellular assays confirmed inhibition of cell proliferation, migration, and angiogenic potential of GBM treated with GO-PEG–Drug conjugates. Ultimately, GBM U87 cells assumed programmed cell death at a very low concentration due to nanocarrier-mediated drug delivery along with the chosen combination of drugs. Together, this study demonstrated the advantage of GO-PEG mediated combined delivery of CPI444 and vatalanib drugs with increased permeability, a three-pronged combinatorial strategy toward effective GBM treatment.

Dendrimer-Functionalized Nanodiamonds as Safe and Efficient Drug Carriers for Cancer Therapy: Nucleus Penetrating Nanoparticles

Nanodiamonds (NDs) are increasingly being assessed as potential candidates for drug delivery in cancer cells and they hold great promise in overcoming the side effects of traditional chemotherapeutics. In the current work, carboxylic acid functionalized nanodiamonds (ND-COOH) were covalently modified with poly(amidoamine) dendrimer (PAMAM) to form amine-terminated nanodiamonds (NP). Unlike ND-COOH, the chemically modified nanodiamond platform NP revealed a pH-independent aqueous dispersion stability, enhancing its potential as an effective carrier. Physical encapsulation of poorly water soluble cabazitaxel (CTX) drug on NP formed ND-PAMAM-CTX (NPC) nanoconjugates and substantially reduced the size of CTX from micrometer to nanometer. CTX was localized within the pores of nanoparticle aggregates and the cavities of the PAMAM dendrimer, thus facilitating the loaded drug's controlled and sustained release. NPC's cumulative CTX release efficiency was determined to be ∼95% at pH 4 after 96 h. A high cellular uptake of NPC both within the cytoplasm and nucleus of U87 cells is confirmed, accounting for a reduced IC₅₀ value (1 nM). Both the cell cycle and Western blot analyses confirmed enhanced cell death and suppressed tubulin protein expression in NPC-treated cells. A significantly high inhibition to cell division with early apoptosis and reduced metastasis demonstrates the effective loading of CTX dosages on the nanocarrier. The present work highlights the potential of a newly designed nanocarrier NP as an efficient nanocargo for cellular delivery applications and may provide future insights to treat one of the most aggressive tumors in neuro-oncological research, glioblastoma multiforme (GBM).

Identification of Components of the Hippo Pathway in Hydra and Potential Role of YAP in Cell Division and Differentiation

The Hippo signaling pathway has been shown to be involved in regulating cellular identity, cell/tissue size maintenance and mechanotransduction. The Hippo pathway consists of a kinase cascade which determines the nucleo-cytoplasmic localization of YAP in the cell. YAP is the effector protein in the Hippo pathway, which acts as a transcriptional cofactor for TEAD. Phosphorylation of YAP upon activation of the Hippo pathway prevents it from entering the nucleus and abrogates its function in the transcription of the target genes. In Cnidaria, the information on the regulatory roles of the Hippo pathway is virtually lacking. Here, we report the existence of a complete set of Hippo pathway core components in Hydra for the first time. By studying their phylogeny and domain organization, we report evolutionary conservation of the components of the Hippo pathway. Protein modelling suggested the conservation of YAP-TEAD interaction in Hydra. Further, we characterized the expression pattern of the homologs of yap, hippo, mob and sav in Hydra using whole-mount RNA in situ hybridization and report their possible role in stem cell maintenance. Immunofluorescence assay revealed that Hvul_YAP expressing cells occur in clusters in the body column and are excluded in the terminally differentiated regions. Actively proliferating cells marked by Ki67 exhibit YAP colocalization in their nuclei. Strikingly, a subset of these colocalized cells is actively recruited to the newly developing bud. Disruption of the YAP-TEAD interaction increased the budding rate indicating a critical role of YAP in regulating cell proliferation in Hydra. Collectively, we posit that the Hippo pathway is an essential signaling system in Hydra; its components are ubiquitously expressed in the Hydra body column and play a crucial role in Hydra tissue homeostasis.

Epigenetic Regulation in Hydra: Conserved and Divergent Roles

Transitions in gene regulatory processes responsible for the emergence of specialized cell types and spatiotemporal regulation of developmental signaling prior to the divergence of Cnidaria and Bilateria are poorly understood. As a sister group of Bilateria, the phylum Cnidaria can provide significant insights into these processes. Among the cnidarians, hydrae have been studied for >250 years to comprehend the mechanisms underlying their unique immortality and robust regenerative capacity. Studies on Hydra spp. and other pre-bilaterians alike have advanced our understanding of the evolutionary underpinnings governing eumetazoan tissue development, homeostasis, and regeneration. In addition to its regenerative potential, Hydra exhibits continuously active axial patterning due to its peculiar tissue dynamics. These distinctive physiological processes necessitate large scale gene expression changes that are governed by the multitude of epigenetic mechanisms operating in cells. This review highlights the contemporary knowledge of epigenetic regulation in Hydra with contemporary studies from other members of Cnidaria, as well as the interplay between regulatory mechanisms wherever demonstrated. The studies covered in the scope of this review reveal both ancestral and divergent roles played by conserved epigenetic mechanisms with emphasis on transcriptional regulation. Additionally, single-cell transcriptomics data was mined to predict the physiological relevance of putative gene regulatory components, which is in agreement with published findings and yielded insights into the possible functions of the gene regulatory mechanisms that are yet to be deciphered in Hydra, such as DNA methylation. Finally, we delineate potentially rewarding epigenetics research avenues that can further leverage the unique biology of Hydra.

Differential tissue stiffness of body column facilitates locomotion of Hydra on solid substrates

The bell-shaped members of the Cnidaria typically move around by swimming, whereas the Hydra polyp can perform locomotion on solid substrates in an aquatic environment. To address the biomechanics of locomotion on rigid substrates, we studied the 'somersaulting' locomotion in Hydra We applied atomic force microscopy to measure the local mechanical properties of Hydra's body column and identified the existence of differential Young's modulus between the shoulder region versus rest of the body column at 3:1 ratio. We show that somersaulting primarily depends on differential tissue stiffness of the body column and is explained by computational models that accurately recapitulate the mechanics involved in this process. We demonstrate that perturbation of the observed stiffness variation in the body column by modulating the extracellular matrix polymerization impairs the 'somersault' movement. These results provide a mechanistic basis for the evolutionary significance of differential extracellular matrix properties and tissue stiffness.

Epigenomic landscape of enhancer elements during Hydra head organizer formation

BACKGROUND

Axis patterning during development is accompanied by large-scale gene expression changes. These are brought about by changes in the histone modifications leading to dynamic alterations in chromatin architecture. The cis regulatory DNA elements also play an important role towards modulating gene expression in a context-dependent manner. Hydra belongs to the phylum Cnidaria where the first asymmetry in the body plan was observed and the oral-aboral axis originated. Wnt signaling has been shown to determine the head organizer function in the basal metazoan Hydra.

RESULTS

To gain insights into the evolution of cis regulatory elements and associated chromatin signatures, we ectopically activated the Wnt signaling pathway in Hydra and monitored the genome-wide alterations in key histone modifications. Motif analysis of putative intergenic enhancer elements from Hydra revealed the conservation of bilaterian cis regulatory elements that play critical roles in development. Differentially regulated enhancer elements were identified upon ectopic activation of Wnt signaling and found to regulate many head organizer specific genes. Enhancer activity of many of the identified cis regulatory elements was confirmed by luciferase reporter assay. Quantitative chromatin immunoprecipitation analysis upon activation of Wnt signaling further confirmed the enrichment of H3K27ac on the enhancer elements of Hv_Wnt5a, Hv_Wnt11 and head organizer genes Hv_Bra1, CnGsc and Hv_Pitx1. Additionally, perturbation of the putative H3K27me3 eraser activity using a specific inhibitor affected the ectopic activation of Wnt signaling indicating the importance of the dynamic changes in the H3K27 modifications towards regulation of the genes involved in the head organizer activity.

CONCLUSIONS

The activation-associated histone marks H3K4me3, H3K27ac and H3K9ac mark chromatin in a similar manner as seen in bilaterians. We identified intergenic cis regulatory elements which harbor sites for key transcription factors involved in developmental processes. Differentially regulated enhancers exhibited motifs for many zinc-finger, T-box and ETS related TFs whose homologs have a head specific expression in Hydra and could be a part of the pioneer TF network in the patterning of the head. The ability to differentially modify the H3K27 residue is critical for the patterning of Hydra axis revealing a dynamic acetylation/methylation switch to regulate gene expression and chromatin architecture.

Molecular signature of an ancient organizer regulated by Wnt/β-catenin signalling during primary body axis patterning in Hydra

Wnt/β-catenin signalling has been shown to play a critical role during head organizer formation in Hydra. Here, we characterized the Wnt signalling regulatory network involved in formation of the head organizer. We found that Wnt signalling regulates genes that are important in tissue morphogenesis. We identified that majority of transcription factors (TFs) regulated by Wnt/β-catenin signalling belong to the homeodomain and forkhead families. Silencing of Margin, one of the Wnt regulated homeodomain TFs, results in loss of the ectopic tentacle phenotype typically seen upon activation of Wnt signalling. Furthermore, we show that the Margin promoter is directly bound and regulated by β-catenin. Ectopic expression of Margin in zebrafish embryos results in body axis abnormalities suggesting that Margin plays a role in axis patterning. Our findings suggest that homeobox TFs came under the regulatory umbrella of Wnt/β-catenin signalling presumably resulting in the evolution of primary body axis in animal phyla.

NF-κB Signaling and IL-4 Signaling Regulate SATB1 Expression via Alternative Promoter Usage During Th2 Differentiation

SATB1 is a genome organizer protein that is expressed in a lineage specific manner in CD4⁺ T-cells. SATB1 plays a crucial role in expression of multiple genes throughout the thymic development and peripheral differentiation of T cells. Although SATB1 function has been subjected to intense investigation, regulation of SATB1 gene expression remains poorly understood. Analysis of RNA-seq data revealed multiple transcription start sites at the upstream regulatory region of SATB1. We further demonstrated that SATB1 gene is expressed via alternative promoters during T-helper (Th) cell differentiation. The proximal promoter “P1” is used more by the naïve and activated CD4⁺ T-cells whereas the middle “P2” and the distal “P3” promoters are used at a significantly higher level by polarized T-helper cells. Cytokine and TCR signaling play crucial roles toward SATB1 alternative promoter usage. Under Th2 polarization conditions, transcription factor STAT6, which operates downstream of the cytokine signaling binds to the P2 and P3 promoters. Genetic perturbation by knockout and chemical inhibition of STAT6 activation resulted in the loss of P2 and P3 promoter activity. Moreover, chemical inhibition of activation of NF-κB, a transcription factor that operates downstream of the TCR signaling, also resulted in reduced P2 and P3 promoter usage. Furthermore, usage of the P1 promoter correlated with lower SATB1 protein expression whereas P2 and P3 promoter usage correlated with higher SATB1 protein expression. Thus, the promoter switch might play a crucial role in fine-tuning of SATB1 protein expression in a cell type specific manner.

Cellular and Molecular Mechanisms of Hydra Regeneration

Regeneration of lost body parts is essential to regain the fitness of the organism for successful living. In the animal kingdom, organisms from different clades exhibit varied regeneration abilities. Hydra is one of the few organisms that possess tremendous regeneration potential, capable of regenerating complete organism from small tissue fragments or even from dissociated cells. This peculiar property has made this genus one of the most invaluable model organisms for understanding the process of regeneration. Multiple studies in Hydra led to the current understanding of gross morphological changes, basic cellular dynamics, and the role of molecular signalling such as the Wnt signalling pathway. However, cell-to-cell communication by cell adhesion, role of extracellular components such as extracellular matrix (ECM), and nature of cell types that contribute to the regeneration process need to be explored in depth. Additionally, roles of developmental signalling pathways need to be elucidated to enable more comprehensive understanding of regeneration in Hydra. Further research on cross communication among extracellular, cellular, and molecular signalling in Hydra will advance the field of regeneration biology. Here, we present a review of the existing literature on Hydra regeneration biology and outline the future perspectives.

A comprehensive epigenome map of Plasmodium falciparum reveals unique mechanisms of transcriptional regulation and identifies H3K36me2 as a global mark of gene suppression

Background

Role of epigenetic mechanisms towards regulation of the complex life cycle/pathogenesis of Plasmodium falciparum, the causative agent of malaria, has been poorly understood. To elucidate stage-specific epigenetic regulation, we performed genome-wide mapping of multiple histone modifications of P. falciparum. Further to understand the differences in transcription regulation in P. falciparum and its host, human, we compared their histone modification profiles.

Results

Our comprehensive comparative analysis suggests distinct mode of transcriptional regulation in malaria parasite by virtue of poised genes and differential histone modifications. Furthermore, analysis of histone modification profiles predicted 562 genes producing anti-sense RNAs and 335 genes having bidirectional promoter activity, which raises the intriguing possibility of RNA-mediated regulation of transcription in P. falciparum. Interestingly, we found that H3K36me2 acts as a global repressive mark and gene regulation is fine tuned by the ratio of activation marks to H3K36me2 in P. falciparum. This novel mechanism of gene regulation is supported by the fact that knockout of SET genes (responsible for H3K36 methylation) leads to up-regulation of genes with highest occupancy of H3K36me2 in wild-type P. falciparum. Moreover, virulence (var) genes are mostly poised and marked by a unique set of activation (H4ac) and repression (H3K9me3) marks, which are mutually exclusive to other Plasmodium housekeeping genes.

Conclusions

Our study reveals unique plasticity in the epigenetic regulation in P. falciparum which can influence parasite virulence and pathogenicity. The observed differences in the histone code and transcriptional regulation in P. falciparum and its host will open new avenues for epigenetic drug development against malaria parasite.

Electronic supplementary material

The online version of this article (doi:10.1186/s13072-015-0029-1) contains supplementary material, which is available to authorized users.

Genome-wide screening reveals the emergence and divergence of RTK homologues in basal Metazoan Hydra magnipapillata

Receptor tyrosine kinases (RTKs) are key components of cell-cell signalling required for growth and development of multicellular organisms. It is therefore likely that the divergence of RTKs and associated components played a significant role in the evolution of multicellular organisms. We have carried out the present study in hydra, a diploblast, to investigate the divergence of RTKs after parazoa and before emergence of triploblast phyla. The domain-based screening using Hidden Markov Models (HMMs) for RTKs in Genomescan predicted gene models of the Hydra magnipapillata genome resulted in identification of 15 RTKs. These RTKs have been classified into eight families based on domain architecture and homology. Only 5 of these RTKs have been previously reported and a few of these have been partially characterized. A phylogeny-based analysis of these predicted RTKs revealed that seven subtype duplications occurred between 'parazoan-eumetazoan split' and 'diploblast-triploblast split' in animal phyla. These results suggest that most of the RTKs evolved before the radiata-bilateria divergence during animal evolution.

Diversity and divergence among the tribal populations of India

Tribal populations of the Indian subcontinent have been of longstanding interest to anthropologists and human geneticists. To investigate the relationship of Indian tribes to Indian castes and continental populations, we analyzed 45 unlinked autosomal STR loci in 9 tribal groups, 8 castes, and 18 populations from Africa, Europe and East Asia. South Indian tribal populations demonstrate low within-population heterozygosity (range: 0.54 - 0.69), while tribal populations sampled further north and east have higher heterozygosity (range: 0.69 - 0.74). Genetic distance estimates show that tribal Indians are more closely related to caste Indians than to other major groups. Between-tribe differentiation is high and exceeds that for eight sub-Saharan African populations (4.8% vs. 3.7%). Telugu-speaking populations are less differentiated than non-Telugu speakers (F(ST): 0.029 vs. 0.079), but geographic distance was not predictive of genetic affinity between tribes. South Indian tribes show significant population structure, and individuals can be clustered statistically into groups that correspond with their tribal affiliation. These results are consistent with high levels of genetic drift and isolation in Indian tribal populations, particularly those of South India, and they imply that these populations may be potential candidates for linkage disequilibrium and association mapping.

Management of cardiac arrhythmias in acute coronary syndromes

A variety of atrial and ventricular arrhythmias are encountered in patients with acute coronary syndromes. These include both brady and tachyarrhythmias of supraventricular and ventricular origin. Sinus bradycardia and atrial fibrillation are the most common of supraventricular origin. Ventricular arrhythmias that merit consideration include premature ventricular complexes, accelerated idioventricular rhythm, ventricular tachycardia, and ventricular fibrillation. Intraventricular and atrioventricular conduction blocks associated with acute coronary syndromes include bundle branch blocks, fascicular blocks, and various degrees of atrioventricular block. A review of management of these arrhythmias is presented.

Role of the catheter in the treatment of cardiac arrhythmias

During the last decade, there has been a remarkable shift away from drug therapy toward catheter-based treatment of many tachyarrhythmias. Catheter ablation using radiofrequency energy has been shown to provide a cure for many supraventricular and ventricular tachycardias with excellent safety and has now become the first line of treatment. A review of biophysics and biology of radiofrequency energy, the technique of catheter ablation, and its application in the treatment of specific tachycardias encountered in clinical practice is presented.

Segregation analysis of regional fat distribution in families from Andhra Pradesh, India

OBJECTIVE

Segregation analysis was used to examine the major gene evidence for regional fat distribution and whether the effects of covariates such as energy variables (intake and expenditure) or total subcutaneous fat, impact on the major gene inference.

SUBJECTS

The data consist of measurements made on 1691 individuals in 432 pedigrees residing in the Chittor district of Andhra Pradesh, India, during the period from January 1989 to February 1990.

MEASUREMENTS

Fat distribution was computed as the ratio of trunk skinfold sum (subscapular + suprailiac + abdominal) to extremity skinfold sum (biceps + triceps + medial calf). The trunk/extremity skinfold ratio (TER) was also analyzed after adjusting for the amount of energy expended in various activities and energy intake (TER-E), as well as after adjusting for overall level of fatness as measured by the sum of six skinfolds (TER-SF6).

METHODS

Segregation analysis was applied using the unified model (POINTER).

RESULTS

For the TER all of the conditions needed to satisfy a major gene hypothesis were met, and a putative recessive locus in the presence of a multifactorial component was inferred. Adjusting the TER for energy intake (EI) and energy expenditure (EE) did not change these results. However, adjusting for total subcutaneous fat did alter the results. Specifically, after removing the effects due to total fat, there was a major non-Mendelian effect (free tau s) with additional multifactorial influences, and with generation heterogeneity in both components.

CONCLUSIONS

A putative major locus for fat distribution as indexed by the TER was found. However, further analyses suggested the hypothesis that this major gene may be primarily for total fat with secondary effects on fat distribution (that is, major gene pleiotropy). The possibility that there is a second locus that is modified by interactions with gender and age, and that impacts on the preferential accumulation of fat in the trunk vs extremity depots could be inferred.

Multiple origins of the mtDNA 9-bp deletion in populations of South India

The origins and genetic affinities of the more than 500 tribal populations living in South Asia are widely disputed. This may reflect differential contributions that continental populations have made to tribal groups in South Asia. We assayed for the presence of the intergenic COII/tRNALys 9-bp deletion in human mtDNA in 646 individuals from 12 caste and 14 tribal populations of South India and compared them to individuals from Africa, Europe, and Asia. The 9-bp deletion is observed in four South Indian tribal populations, the Irula, Yanadi, Siddi, and Maria Gond, and in the Nicobarese. Length polymorphisms of the 9-bp motif are present in the Santal, Khonda Dora, and Jalari, all of whom live in a circumscribed region on the eastern Indian coast. Phylogenetic analyses of mtDNA control region sequence from individuals with the 9-bp deletion indicate that it has arisen independently in some Indian tribal populations. Other 9-bp deletion haplotypes are likely to be of Asian and African origin, implying multiple origins of the 9-bp deletion in South India. These results demonstrate varying genetic affinities of different South Indian tribes to continental populations and underscore the complex histories of the tribal populations living in South Asia.

Ventricular tachycardia and sudden cardiac death

As we approach the new millennium, treatment of survivors of cardiac arrest and prevention of sudden cardiac death (SCD) are the two most important problems confronting contemporary cardiology practice. Sudden cardiac death occurs as a result of ventricular tachycardia (VT) degenerating into ventricular fibrillation (VF). Several major arrhythmia treatment trials completed during the last decade have significantly changed the way we treat patients with ventricular arrhythmias. In patients with sustained VT and aborted SCD, only treatment with implantable cardioverter defibrillator (ICD) has been shown to significantly increase survival. Amiodarone and sotalol, though very useful in the treatment of VT and VF, do not improve survival as significantly as ICD therapy. Use of Class I antiarrhythmics may adversely affect survival. Primary prevention of SCD in patients with a recent myocardial infarction (MI) and in patients with cardiomyopathy and congestive heart failure (CHF) is limited by our inability to accurately identify patients at risk of SCD. Among the many tests available to identify patients at risk of SCD, decreased left ventricular ejection fraction (LVEF) and presence of non-sustained VT appear to be most useful. To date, only beta adrenoceptor blockers have been shown to improve survival in post-MI patients as well as in patients with cardiomyopathy and CHF. Use of amiodarone is controversial in these patients. Treatment with ICD of post-MI patients with decreased LVEF and inducible sustained VT at electrophysiology study improves survival.

Mitral valve prolapse. A common cardiac diagnosis in women

Mitral Valve Prolapse (MVP) is the most frequently diagnosed cardiac valvular abnormality. It is a primary disorder with familial occurrence. MVP is a disease of the young with a significantly higher incidence in women compared to men. The most characteristic clinical finding is a midsystolic click and late systolic murmur detected on cardiac auscultation. Two-dimensional echocardiography is the diagnostic tool of choice. 2D echo also helps in stratification of MVP patients at risk of developing serious complications. Although MVP runs a benign course in the majority of patients, significant complications may occur. These include progressive mitral regurgitation with heart failure, infective endocarditis, systemic emboli, cardiac arrhythmias, and rarely sudden death. The focus of therapy is reassurance and symptom relief when possible. It is important to recognize those patients that are at risk of developing significant complications, follow them closely, and intervene appropriately when complications occur.

Age and sex variation of blood pressure in the population of Andhra Pradesh

The blood pressure investigation was carried out on 530 males and 745 females of the general population including ages from 10 to 80 years. The increase of blood pressure with advancing age was evident both in males and females. The mean systolic pressures were greater in males upto 40 to 49 years and thereafter females showed greater mean values. However, diastolic pressure values were greater in males although. This is in agreement with the studies from India. Sex difference was evident in younger ages only.

Dietary vitamin E and selenium effects on resistance to oxidative stress in rat liver mitochondria

Mitochondria-rich fractions isolated from livers of rats fed diets differing in their vitamin E (E) and/or selenium (Se) contents were subjected to NADPH/ADP/Fe(3+)- dependent assays of lipid peroxidation. Addition of GSH resulted in an inhibition, or lag period, of lipid peroxidation in mitochondria from rats supplemented with E. This effect was independent of the Se status of the rats. Addition of GSH + GSSG did not potentiate the lag period over that observed with GSH alone. Significant changes in mitochondrial alpha-TH during lipid peroxidation, either in the presence or absence of GSH, were not observed. Total protein thiol (PrSH) content of native mitochondria was lower in rats fed a diet deficient in both E and Se, compared to the other dietary groups. Addition of GSH or GSH + GSSG maintained mitochondrial PrSH at higher levels during lipid peroxidation than in control assays without added GSH/GSSG. Addition of GSSG alone decreased PrSH in mitochondria prepared from all rats regardless of their E or Se status. Reduced ubiquinone-9 (U-9) and the % of total U-9 and U-10 in the reduced form were significantly decreased in liver tissue from rats fed the diet deficient in both E and Se.

Fatty acid profile and the atherogenic risk in fish consuming and non fish consuming people

Epidemiological studies have indicated a lower incidence of cardiovascular disease in populations with a high habitual intake of marine fish and fish oils, and this apparent protection may be due to the presence of n-3 fatty acids in the dietary fish. Two populations, a rish consuming one from coastal area and an inland one with non fish consuming from Nellore district or South India were selected for the present study. A total of one thousand healthy subjects were randomly chosen (500 in each population) from both sexes, aged from 20 to 70 years. The concentration of serum cholesterol, triacylglycerol and LDL-cholesterol were significantly lower in fish consumers, whereas HDL-cholesterol was higher in fish consumers than in non fish consumers. The difference between the percent quantities of the three n-3 fatty acids (eicosapentaenoic, docosapentaenoic and docosahexaenoic acids) was highly significant (p < 0.001) with a greater value in fish consumers.

Commingling analysis of adiposity in an Indian population

The distributions of five adiposity phenotypes were assessed for the presence of commingling in a sample of 756 adults (> or = 30 years old), residing in the Chittoor district of Andhra Pradesh, India. Three measures of generalized fatness (body mass index, the sum of six skinfolds and the sum of three trunk skinfolds) and two indicators of fat patterning (the ratio of trunk to extremity subcutaneous fat and the ratio of the subscapular skinfold to the sum of the subscapular and the supra-iliac skinfolds) were analysed. Each phenotype was adjusted for the effects of (i) age within sex, and (ii) age, energy intake and energy expenditure within sex. The distribution of each phenotype, under both adjustment schemes, was assessed for evidence of commingling. The commingling analyses were performed separately for males (n = 397) and females (n = 359), and evidence for heterogeneity in the distribution of each phenotype, by sex, was evaluated. There is evidence of commingling in the distribution of each phenotype, under both adjustment schemes. Conclusions regarding the distributions of these phenotypes are, however, influenced by the specific adjustments made to the data. In general, the measures of generalized fatness are more sensitive than measures of fat patterning to the specific adjustments applied to the data. Interestingly, and in contrast with the majority of commingling analyses of adiposity, the smallest components of the commingled distributions often have the lowest mean phenotypic value.

Assessment of adiposity in an Indian population: familial correlations

Familial correlations for five measures of adiposity were assessed using data from 473 nuclear families residing in the Chittoor district of Andhra Pradesh, India. Fat patterning, measured as the ratio of trunk to extremity subcutaneous fat, and the ratio of the subscapular to the sum of the subscapular and suprailiac skinfolds, and three measures of generalized fatness: body mass index, the sum of six skinfolds and the sum of three trunk skinfolds were analyzed. Maximum likelihood estimates of the familial correlations were obtained for each phenotype, after adjusting for the effects of (1) age within sex, and (2) current levels of energy intake and expenditure, and age within sex. Hypotheses regarding sex-specific, and generational differences in these correlations were assessed for each phenotype, under both adjustment schemes. The strength and pattern of the familial correlations for the three measures of generalized fatness were markedly influenced by the specific adjustments applied to the data. In contrast, the familial correlations for the fat patterning phenotypes were quite similar under the two adjustment schemes. Comparison of our results with previously published data indicates that the familial correlations for a subset of these adiposity measures may be heterogeneous across populations.

Familial resemblance of blood pressure with residual household environmental effects in consanguineous and nonconsanguineous families from Andhra Pradesh, India

Familial aggregation of blood pressure (BP), both systolic (SBP) and diastolic (DBP), was examined in consanguineous and nonconsanguineous families from southern India. Path analysis of BP suggests inbreeding effects, with the genetic variance for SBP being lower in the sample that included inbred families. Specifically, genetic heritability for SBP was 38% in the nonconsanguineous sample but only 23% in the combined sample. Genetic heritability for DBP (30%) did not vary by sample, nor were sample differences in cultural heritability detected for either SBP (over 35%) or DBP (about 18%). These findings are remarkably similar to those in a French-Canadian population of Quebec; both reports found a considerably larger effect of the home environment on BP than previous studies.

The electrocardiogram in the diagnosis of acute myocardial infarction

Diagnosis of acute myocardial infarction as early in the course of its evolution as possible is an important requirement for successful coronary reperfusion. In spite of the availability of many newer diagnostic methods, electrocardiography retains its preeminent place in the diagnosis of acute myocardial infarction. The value and limitations of the electrocardiogram in the diagnosis of acute myocardial infarction are reviewed.

Blood pressure in relation to skinfold thickness in the population of Andhra Pradesh

The blood pressure of 1275 subjects of both sexes in relation to four skinfolds at biceps, triceps, subscapular and supra-iliac was studied. A positive relationship is observed between these two variables. The mean systolic and diastolic pressures increase from lower to higher skinfold thickness groups in both sexes for all the four skinfolds. The sex difference is conspicuous and significant for systolic pressure. However only a few groups show significant sex difference for diastolic pressure. In males the correlations between blood pressure and skinfolds were significant, while in females it is significant between diastolic blood pressure and biceps and triceps skin thicknesses only.

Substoichiometric determination of zinc with potassium ethyl xanthate

A rapid radiochemical method has been designed for the determination of microgram quantities of zinc, based on the substoichiometric isotope dilution, using potassium ethyl xanthate as the extraction reagent. pH 5.5 in acetate buffers and chloroform as the extractant were found to be suitable for quantitative substoichiometric extraction. The influence of the diverse ions on the extraction was studied. The zinc contents of a medicinal preparation and biological samples were determined by the present method.

Lipid profiles among fish-consuming coastal and non-fish-consuming inland populations

Serum lipid profiles were examined in 100 individuals of fish-consuming coastal and 109 individuals of non-fish-consuming inland populations. The fish-consuming population showed lower mean serum cholesterol, triacylglycerols and significantly higher levels of HDL cholesterol and phospholipids. The bleeding time and clotting time were significantly prolonged in the fish-eating population. Thus the fish-consuming population showed lower risk factors of coronary heart disease when compared to the non-fish-consuming population.

Substoichiometric radiochemical determination of silver with potassium ethyl xanthate in photofilm washings

An accurate and rapid radiochemical method has been developed for the determination of microgram amount of silver employing potassium ethyl xanthate as a substoichiometric radiochemical reagent. The light yellow coloured silver ethyl xanthate formed was extracted into nitrobenzene from sulphuric acid media. The effect of foreign ions on the extraction was studied. The method was applied to the determination of silver content in photofilm washings.

Determination of cadmium in water samples by substoichiometric radiochemical method employing potassium ethyl xanthate

A radiochemical method has been developed for the determination of microgram amounts of cadmium based on the substoichiometric extraction of its 1:2 complex with potassium ethyl xanthate into 1:4 v/v mixture of pyridine and ethyl acetate from 2.5 M sodium formate. 10-90 micrograms of cadmium was determined with an average error of +/- 1.96%. The method developed was successfully applied to the determination of Cd contents in water samples.

Blood pressure in relation to smoking

The present study of blood pressure among 1275 smokers and non-smokers from Andhra Pradesh reveals slightly higher mean blood pressures among smokers in most of the age groups. This is in contrast to most of the studies. The variation of blood pressure among smokers and non-smokers is significant.

Pulmonary monosporosis: an uncommon pulmonary mycotic infection

Pulmonary monosporosis is an uncommon form of fungal disease of the lung and bronchorespiratory passages. To date, only six isolated cases have been reported in the literature. It is the purpose of this communication to present the clinical findings, laboratory data, radiographic appearance, and description of the pathology findings in three additional cases identified at the Missouri State Sanatorium. The fungus Monosporium apiospermum is present in the soil and has a world-wide distribution. It has been shown to produce localized lesions in the foot called maduromycosis. Pulmonary infection due to this fungus has no characteristic clinical pattern, but the cultural characteristics of M. apiospermum permit specific identification. Histologically, the pulmonary involvement shows a variegated non-specific pattern. In the majority of cases, well-defined, predisposing factors are present. A review of the reported six cases and a study of our three cases strengthens our belief that the organism acts as a secondary invader. To date, no mode of therapy has appeared to exert a beneficial influence on the course of the disease. To our knowledge, no clinical trial using any of the antifungal agents has been attempted. Surgical treatment is indicated whenever the lesions are considered resectable. From our observations, we conclude that pulmonary infection with M. apiospermum could be recognized more frequently if physicians were more aware of this fungal infection and if the mycology laboratories would take additional care in specific identification.