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Biomedical subjects

Urvashi Bhardwaj

Publications and source records attributed to Urvashi Bhardwaj.

6 recordsLinked to original sources
PubMed2006

Completely self-contained cell culture system: from storage to use.

In vitro cell culture systems provide researchers the appropriate tools for effectively studying cell growth and differentiation, understanding cellular response to specific environmental stimuli, and elucidating the function of heterologous biological molecules produced from expression systems. All in vitro cell culture systems require a specific culture media formulated to the nutritional and metabolic requirements of the particular cell type to be cultured. However, the complexity of these systems varies depending on the model organism origin of the cells being cultured (e.g., bacteria, plants, yeast or animal). Unlike bacteria and yeast, mammalian cell cultures require sophisticated auxiliary technologies (e.g., controlled gas mixtures and pressure flow systems, specialized facilities and equipment) and careful handling by trained personnel. These complex requirements pose a limitation to transferring cells to and from remote field locations for investigations. Furthermore, this limitation is a technical hurdle in the development of technologies involving use of live cells (e.g., cytosensors). We identified a novel and unrealized feature in the conventional cell culture system that may be exploited to adapt simple existing technologies to form a portable apparatus for storing and growing cells. The approach we describe is a completely self-contained cell culture system that not only will bring down the cost of culturing cells but also will expand cell culture applications in medicine, research, environmental health, and safety.

Animals↗
PubMed2005

Molecular genetic confirmatory testing from newborn screening samples for the common African-American, Asian Indian, Southeast Asian, and Chinese beta-thalassemia mutations.

beta-Thalassemia is a serious health problem in the United States, especially in California, due to increased Asian immigration. Neonatal screening by using high-performance liquid chromatography (HPLC) or isoelectric focusing (IEF) may lead to confusion due to interactions of various hemoglobinopathies with beta-thalassemia. Our purpose was to develop single-tube multiplexed PCR assays using original neonatal screening specimens to identify the mutations responsible for beta-thalassemia in order to expedite diagnostic confirmation. Primers were designed for two to six common ethnic-specific mutations using the amplification refractory mutation system (ARMS). This multiplex ARMS approach was standardized using DNA samples with known mutations for beta-thalassemia in those of Asian (Southeast Asian, Chinese, and Asian Indian) and African-American descent. Specimens from African-American neonates were tested for two mutations (-88 and -29); Asian Indians for five mutations (IVSI-1, IVSI-5, codons (Cd) 41/42, Cd 8/9, and 619-bp deletion); Chinese, Taiwanese, and Southeast Asians for seven mutations (Cd 41/42, Cd 17, -28, IVSII-654, Cd 71/72, IVSI-5, and IVSI-1). We identified each of these beta-thalassemia mutations in multiplexed ARMS from positive control samples. We tested 25 anonymized dried blood specimens from neonates who had been diagnosed with beta-thalassemia and who also belonged to these ethnic groups. We detected a mutation specific to the neonate's ethnic group using the ARMS approach in nearly all specimens, and the results were confirmed by sequencing. Multiplexed ARMS for ethnic-specific beta-thalassemia mutations from the original newborn screening dried blood specimens is a rapid and efficient approach for diagnostic confirmation.

Asian People↗
PubMed2005

Multiplex-PCR assay for the deletions causing hereditary persistence of fetal hemoglobin.

INTRODUCTION: Hereditary persistence of fetal hemoglobin (HPFH) is a benign condition caused by the failure of normal switching from the fetal to the adult beta-globin gene, resulting in continuous production of fetal hemoglobin beyond the perinatal period. To date, eight deletions of variable size and position have been reported for HPFH. Southern hybridization and PCR are the most common methods used to detect each deletion. AIM: Our aim was to develop a multiplex-PCR assay to detect these deletions in a single tube in order to facilitate rapid and accurate molecular diagnosis. METHODS AND RESULTS: This report is the first application of multiplex-gap-PCR to detect all HPFH deletions simultaneously to expedite diagnosis. The deletion breakpoints were precisely identified for each deletion and primers were designed in the unique regions across the breakpoints of HPFH-1 (Black), HPFH-2 (Ghanaian), HPFH-3 (Asian Indian), HPFH-4 (Italian), HPFH-5 (Italian), HPFH-6 (Vietnamese), HPFH-7 (Kenyan), and SEA-HPFH (Southeast Asian). As many as 16 primers were used in a single amplification reaction by adjusting the relative primer concentrations. The multiplex-PCR approach was standardized on known positive control samples. We identified unique deletion-specific products for each deletion. The results were confirmed by sequence analysis. CONCLUSIONS: We conclude that our multiplex-gap PCR strategy provides the most rapid and accurate diagnosis for the deletions in the beta-globin gene cluster causing HPFH.

Fetal Hemoglobin↗
PubMed2003

DNA diagnosis confirms hemoglobin deletion in newborn screen follow-up.

Molecular genetic confirmatory testing with polymerase chain reaction amplification is integral to neonatal hemoglobinopathy screening programs. In this study, we demonstrate applicability of polymerase chain reaction-based testing for the common deletions in blacks responsible for hereditary persistence of fetal hemoglobin. This approach will provide rapid diagnostic clarification in newborn screening follow-up.

Alleles↗
PubMed2002

Rapid confirmation of Southeast Asian and Filipino alpha-thalassemia genotypes from newborn screening specimens.

Alpha(+)-thalassemia (-alpha) is prevalent throughout tropical and subtropical regions of world, whereas alpha(0)-thalassemia (--) occurs at higher frequency in Southeast Asia. Homozygosity for the alpha(0)-thalassemia deletion (--/--) is a serious health problem in Southeast Asia and the Philippines and is responsible for the majority of hydrops fetalis in this region. Asian immigration in United States has impacted the demography of genetic disease in U.S. As Asians comprise of 10% of all California births and represent a population at highest risk for alpha(0)-thalassemia, we developed a rapid and efficient PCR approach to detect the common alpha(0)-thalassemia deletions in Southeast Asians and Filipinos using newborn screening specimen.

Asia, Southeastern↗