PubMed Health⌕ Search

Biomedical subjects

Ashis Mukhopadhyay

Publications and source records attributed to Ashis Mukhopadhyay.

6 recordsLinked to original sources
PubMed2006

Disassembly of layer-by-layer films of plasmid DNA and reducible TAT polypeptide.

This paper reports the disassembly of layer-by-layer (LbL) films of plasmid DNA and a reducible cationic polypeptide. To utilize a reducing microenvironment of cellular plasma membrane as a potential trigger, LbL films are assembled to contain both DNA and the TAT-based polypeptide (PTAT) with reducible disulfide bonds in the backbone. The assembly and disassembly processes are monitored by goniometry, ellipsometry, and atomic force microscopy (AFM). The structure of the PTAT films is compared with that of non-reducible poly(L-lysine) (PLL) films. Both PTAT and PLL films exhibit exponential growth but with the contact angle alternating between characteristic values. Ellipsometry and AFM show a gradual and complete disassembly of the PTAT but not the PLL films in a 24h period in the reducing environment in vitro. This study suggests a potential of using reducible LbL films for controlled DNA delivery.

DNA↗
PubMed2006

Molecular profiling of chronic myeloid leukemia in eastern India.

Molecular breakpoint of the BCR-ABL fusion gene has been characterized for 122 chronic myeloid leukemia patients. Out of 122 cases, 33 b2a2, 69 b3a2, 2 e1a2, and 2 e19a2 cases have been detected. Six coexpressed both b2a2 and b3a2 transcripts. All the coexpressing samples had an A>G polymorphism at the putative splice branchpoint in intron 13. The T>C polymorphism in exon 13, reported to be linked to coexpression, was not present in all the coexpressing patients. No correlation of transcript type with platelet count was detected. Those expressing b2a2 transcript were diagnosed at relatively younger age and with higher white blood cell count, in agreement with other reports. However, the correlation was not statistically significant.

Adult↗
PubMed2004

Profile of beta-thalassemia in eastern India and its prenatal diagnosis.

OBJECTIVE: To control the birth of thalassemic children in India. METHODS: Mutations present in the population of eastern India and in carrier parents seeking prenatal diagnosis were detected by the PCR-based technique of ARMS (amplification refractory mutation system) or gap-PCR. To screen for maternal tissue contamination in CVS, haplotypes associated with the beta-globin gene clusters were constructed using six polymorphic restriction sites. Prenatal diagnosis was accomplished by checking presence of parental mutation in the DNA from chorionic villus sampling (CVS) collected at 8 to 10 weeks' gestation by appropriate technique. RESULTS: Six hundred and fifty (650) unrelated beta-thalassemia chromosomes were screened for 11 common mutations to characterize the mutation distribution in this population. Starting from early 2000, 63 families from different parts of West Bengal and from surrounding areas have been offered prenatal counseling for beta-thalassemia. CONCLUSION: The population of this region is conscious and willing to accept prenatal diagnosis as a means of control of thalassemia.

Chorionic Villi Sampling↗
PubMed2004

How confined lubricants diffuse during shear.

The translational diffusion of a fluorescent dye embedded at a dilute concentration in a confined fluid was compared at rest and during shear. The fluid, octamethylcyclotetrasiloxane (OMCTS), was confined between step-free muscovite mica to thickness 3-4 layers. Fluorescence correlation spectroscopy showed that the time scales of intensity-intensity autocorrelation functions were essentially the same during shear and at rest, except they were faster during shear by a factor of 2 to 5. This dynamical probe of how liquids order in molecularly thin films fails to support the hypothesis that shear produced a melting transition.

Journal Article↗
PubMed2002

Contrasting friction and diffusion in molecularly thin confined films.

We study, using fluorescence correlation spectroscopy, translational diffusion in molecularly thin liquids confined within a surface forces apparatus. The diffusion coefficient decreases exponentially from the edges towards the center of the Hertzian contact and further suggests the presence of a small number of distinct diffusion processes. This holds alike a crystallizable fluid (OMCTS) and a glass-former (1,2-propane diol), both of which displayed static friction. We conclude that friction, the average of an ensemble of molecules, masked massively heterogeneous molecular mobility.

Journal Article↗