Publications by authors named "Ritu Kumar"

Haploinsufficiency for is associated with congenital heart disease (CHD) with variable comorbidity of pancreatic or diaphragm defects, although the etiology of disease is not well understood. Here, we used cardiac directed differentiation from human embryonic stem cells (hESCs) as a platform to study GATA6 function during early cardiogenesis. GATA6 loss-of-function hESCs had a profound impairment in cardiac progenitor cell (CPC) specification and cardiomyocyte (CM) generation due to early defects during the mesendoderm and lateral mesoderm patterning stages.

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While Mek1/2 and Gsk3β inhibition ("2i") supports the maintenance of murine embryonic stem cells (ESCs) in a homogenous naïve state, prolonged culture in 2i results in aneuploidy and DNA hypomethylation that impairs developmental potential. Additionally, 2i fails to support derivation and culture of fully potent female ESCs. Here we find that mouse ESCs cultured in 2i/LIF supplemented with lipid-rich albumin (AlbuMAX) undergo pluripotency transition yet maintain genomic stability and full potency over long-term culture.

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Article Synopsis
  • This study looks at what helps and what makes it hard for people to use health technology assessment (HTA) in making health decisions.
  • Researchers found and reviewed thousands of articles to get the best information on HTA from around the world.
  • In the end, they discovered important details about what can improve HTA practices and how to better organize health-related decisions.
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Objective: To provide an update on the use of health technology assessment (HTA) in Asia and lessons for countries seeking to advance HTA.

Methods: Build upon the research by Chootipongchaivat and the World Health Organization identifying eighteen "factors conducive to the development of HTA in Asia." These factors were used to create a balanced scorecard to assess the progress of HTA, measuring progress against each factor in China, India, Indonesia, Malaysia, Philippines, South Korea, Taiwan, Thailand, and Vietnam.

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DNA methylation is essential to mammalian development, and dysregulation can cause serious pathological conditions. Key enzymes responsible for deposition and removal of DNA methylation are known, but how they cooperate to regulate the methylation landscape remains a central question. Using a knockin DNA methylation reporter, we performed a genome-wide CRISPR-Cas9 screen in human embryonic stem cells to discover DNA methylation regulators.

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Background: While mutations in the cardiac type 2 ryanodine receptor (RyR2) have been linked to exercise-induced or catecholaminergic polymorphic ventricular tachycardia (CPVT), its association with polymorphic ventricular tachycardia (PMVT) occurring at rest is unclear. We aimed at constructing a patient-specific human-induced pluripotent stem cell (hiPSC) model of PMVT occurring at rest linked to a single point mutation in RyR2.

Methods: Blood samples were obtained from a patient with PMVT at rest due to a heterozygous RyR2-H29D mutation.

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Background And Aims: Meteorological parameters play a major role in the transmission of infectious diseases such as COVID-19. In this study, we aim to analyze the correlation between meteorological parameters and COVID-19 pandemic in the financial capital of India, Mumbai.

Methods: In this research, we collected data from April 27 till July 25, 2020 (90 days).

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Sphingosine-1-phosphate (S1P) is a bioactive lipid molecule regulating organogenesis, angiogenesis, cell proliferation, and apoptosis. S1P is generated by sphingosine kinases (SPHK1 and SPHK2) through the phosphorylation of ceramide-derived sphingosine. Phenotypes caused by manipulating S1P metabolic enzymes and receptors suggested several possible functions for S1P in embryonic stem cells (ESCs), yet the mechanisms by which S1P and related sphingolipids act in ESCs are controversial.

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Aims: Human embryonic stem cells (hESCs) can be used to generate scalable numbers of cardiomyocytes (CMs) for studying cardiac biology, disease modelling, drug screens, and potentially for regenerative therapies. A fluorescence-based reporter line will significantly enhance our capacities to visualize the derivation, survival, and function of hESC-derived CMs. Our goal was to develop a reporter cell line for real-time monitoring of live hESC-derived CMs.

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Induced pluripotent stem cells (iPSCs) derived by in vitro reprogramming of somatic cells retain the capacity to self-renew and to differentiate into many cell types. Pluripotency encompasses multiple states, with naïve iPSCs considered as ground state, possessing high levels of self-renewal capacity and maximum potential without lineage restriction. We showed previously that activation-induced cytidine deaminase (AICDA) facilitates stabilization of pluripotency during reprogramming.

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Miliary tuberculosis is a lethal form of disseminated tuberculosis (TB), deriving its name from the millet-seed-sized granulomas in multiple organs. As TB still remains a leading cause of morbidity and mortality in India, its disseminated forms need to be diagnosed early to ensure more aggressive treatment at the earliest possible time. However, a considerable number of cases are missed ante-mortem.

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Article Synopsis
  • In 1997, a study was published about how to tell if local vaccine makers can be successful, focusing on their qualities and performance.
  • The authors revisited this study 20 years later to see if their methods still worked in predicting which manufacturers would succeed, especially in low and middle-income countries.
  • They found that to be successful, vaccine makers need to meet global quality standards and adapt to new technologies, along with having support from governments and donors.
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Human disease phenotypes associated with haploinsufficient gene requirements are often not recapitulated well in animal models. Here, we have investigated the association between human GATA6 haploinsufficiency and a wide range of clinical phenotypes that include neonatal and adult-onset diabetes using CRISPR (clustered regularly interspaced short palindromic repeat)/Cas9-mediated genome editing coupled with human pluripotent stem cell (hPSC) directed differentiation. We found that loss of one GATA6 allele specifically affects the differentiation of human pancreatic progenitors from the early PDX1+ stage to the more mature PDX1+NKX6.

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Article Synopsis
  • Primaquine is the only drug that can get rid of certain malaria germs in people, but it can cause problems for those with a specific blood condition called G6PD deficiency.
  • New tests have been created to check G6PD levels quickly, which is important before using primaquine.
  • There are two types of tests: simple ones that give yes or no answers and more complex tools that give a detailed measurement, both of which could help in the fight against malaria.*
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In this article, we present the first case of necrotizing fasciitis affecting the abdominal wall caused by Serratia marcescens and share results of a focused review of S. marcescens induced necrotizing fasciitis. Our patient underwent aorto-femoral bypass grafting for advanced peripheral vascular disease and presented 3 weeks postoperatively with pain, erythema and discharge from the incision site in the left lower abdominal wall and underwent multiple debridement of the affected area.

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Background: Mycobacterium avium complex (MAC) is a ubiquitous pathogen, widely distributed in the environment including water, soil and animals. It is an uncommonly encountered clinical pathogen; primarily causing pulmonary infections in patients with underlying lung disease or disseminated disease in immunocompromised hosts. Sporadically, extra-pulmonary infections have been documented including involvement of the liver, spleen, skin, soft tissue and lymph nodes.

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Background: Today's uncertain HIV funding landscape threatens to slow progress towards treatment goals. Understanding the costs of antiretroviral therapy (ART) will be essential for governments to make informed policy decisions about the pace of scale-up under the 2013 WHO HIV Treatment Guidelines, which increase the number of people eligible for treatment from 17.6 million to 28.

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Activation-induced Cytidine Deaminase (AID) is an essential regulator of B cell diversification, but its full range of action has until recently been an enigma. Based on homology, it was originally proposed to be an RNA-editing enzyme, but so far, no RNA substrates are known. Rather, it functions by deaminating cytidine, and in this manner, coupled with base-excision repair or mismatch repair machinery, it is a natural mutator.

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Background: Well-differentiated gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare tumors with varying metastatic potential. The underlying molecular basis for metastasis by GEP-NETs remains undefined.

Methods: Quantitative PCR and immunohistochemistry (IHC) staining for ubiquitin carboxyl-terminal esterase L1 (UCHL1) gene and protein expression was performed on a group of localized and metastatic well-differentiated GEP-NET samples acquired from a prospectively maintained tissue bank.

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Article Synopsis
  • The study looked at how much stress dental students feel, what causes it, and how it affects them.* -
  • Researchers found lots of studies (4,720) but focused on 124 for detailed analysis and learned that dental training is really stressful for students.* -
  • The stress can harm students' health, and the study suggests more long-term research and ways to help students manage that stress better.*
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The activation-induced cytidine deaminase (AID; also known as AICDA) enzyme is required for somatic hypermutation and class switch recombination at the immunoglobulin locus. In germinal-centre B cells, AID is highly expressed, and has an inherent mutator activity that helps generate antibody diversity. However, AID may also regulate gene expression epigenetically by directly deaminating 5-methylcytosine in concert with base-excision repair to exchange cytosine.

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Gastrointestinal bleeding.

Emerg Med Clin North Am

May 2011

Gastrointestinal bleeding is a common complaint encountered in the emergency department and frequent cause of hospitalization. Important diagnostic factors that increase morbidity and mortality include advanced age, serious comorbid conditions, hemodynamic instability, esophageal varices, significant hematemesis or melena, and marked anemia. Because gastrointestinal bleeding carries a 10% overall mortality rate, emergency physicians must perform timely diagnosis, aggressive resuscitation, risk stratification, and early consultation for these patients.

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Background: Predictors of adverse events (AE) associated with nevirapine use are needed to better understand reports of severe rash or liver enzyme elevation (LEE) in HIV+ women.

Methodology: AE rates following ART initiation were retrospectively assessed in a multi-site cohort of 612 women. Predictors of onset of rash or LEE were determined using univariate and multivariate analyses.

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